The ND and other suggestions were made if the OP was intent on driving from Chicago to the east to help break up the long drive.
You are right. The area between Calais and Prague is a complete and utter wasteland.
Zin, no one said wasteland. But if your original purpose was one stop in eastern France, then sites 11+ hours away by car (maybe more with stops and overnights) - and some of this trip was already going to be stressful- why would you make the drive just to add sites not on your radar? Put another way: on someone else’s radar. Why not prioritize the schools already of interest? OP doesn’t have to drive. But if he does want to add midwest schools, why not do it at the end? If they’re inclined to drive, then do it from Phila or NYC west. They can assess Pittsburgh, Indiana, Kenyon, Grinnell, etc, at the end.
But behind this, I think the eagerness to name extra schools misses what his kids are truly interested in. We only know a little. To me, it becomes about us, not OP and his family. And, for many non-US folks, the driving distances here and traffic near and through US cities are something they’re not fully prepared for.
@lookingforward - There are 8 schools on the OP’s list. They plan to spend 20 days here. It seems they have plenty of time to visit those schools and do quite a bit of sightseeing in the meantime. One can certainly fly between Philadelphia and Chicago, but there are plenty of things to see and do in the rest of the United States so they don’t have to be confined in the northeast corridor.
Put it this way, if one were taking a similar three week trip to Europe, with seven campuses in the UK and one in Prague, which is more appealing trip?
1 - Spend two and half weeks in the UK, and fly to Prague before returning to the states.
2 - Spend a week and half in the UK, then leisurely drive cross-continent so one could see Bruges, Brussels, Strasbourg, Stuttgart and Munich before arriving in Prague.
As for naming schools, if one is driving cross country on a college trip, why not stop off at a school when you are driving nearby? We recently did a summer tour along the eastern seaboard similar to the OP’s, and we looked at more than 20 schools in a two week period.
Mostly we just drove through campus, but we had official tours at some and overnight camps at others. One of the schools that we drove through as an afterthought is now at the top of the list for two of our kids.
Make the extra stops schools relevant to OP’s kids. Visit the schools of known interest before adding. I realize all this will refine as they tour the first schools.
He mentioned “lots of sports, dance, drama and musicals” among her activities and I don’t see comments related to that. Yes, some families do whirlwinds, pack in lots of colleges.and make it successful. But the chain is only as strong as its weakest link. Savvy planning isn’t as simple as, “Oh, let’s do it all, get the most bang for our buck.” It’s knowing the priorities and the possibility their energies may flag, the kids may get hot and bored, they can get lost, sick, whatever. I hate to think the trip is already a blur by the time they reach Maine.
Trains in the US are VERY slow, except for the Acela along the eastern seaboard which is comparable to what you’d find in the UK. However, for NYC/Philly/DC, and even DC to Richmond, you have good trains.
And if it were football season and they could get tickets, it would satisfy the OP’s desire to see an interesting American sporting event. But it is July. So it just doesn’t seem like a school that makes any sense for them. There are 30 colleges along the way if the OP is driving from Chicago to the east coast, this one does not seem to be a particular fit for the OP’s daughter.
OP, I sent you a message.
If you haven’t been on vacation in North America before, I personally recommend driving through the heartland (both of the US and Canada). If I was planning this, the vacation/sightseeing would come first and we’d also stop at a few colleges here and there.
Also, why do your kids want to study in the US?
I just found out about the university colleges in the Netherlands, which are new and aim to provide flexibility and a liberal arts education with an international flavor. They are about the size of an Oxbridge college. Everything’s taught in English and it is much cheaper than full-pay in the States. U of Amsterdam and VU probably are more recognized in the UK and Europe than most LACs here as well.
@valent2016 : after watching the film, if Kenyon doesn’t work, you could easily substitute Bowdoin or Bates or Colby or other LACs located in “small-town America” for the real thing visit. 
BTW, the film makes good points about what education is about, at least, in a Liberal Arts sense (hence, the title). American Pie and The Neighbors it isn’t.
@valent2016, For ED, your daughter should choose the college that she likes the most, period. Don’t worry about its rank on the reach to match continuum.
I believe ED is a good strategy for an under-hooked, full pay international applicant. Admission rates for non-Americans are significantly lower than for US citizens. Schools target a fixed percentage of international students, so, in essence, international applicants are competing with other international applicants, not with the US pool. Many international applicants not only are academically accomplished, but also come with significant diversity advantages.
Colleges are looking for a balanced group of internationals, just as they’re looking for a balanced class overall. Diversity factors such as gender, race, religion, geography, economic status, talent and life experience are all considered. This is especially true of small LACs where each student needs to fulfill more than one demographic and/or talent slot.
Grades, scores, class rank which need to fall within the college’s range are easily assessed, although predicted IB scores can be a complication. It’s the subjective and abstract qualities – essays, letters of recommendation, extracurriculars, talent, demographics, life experience – that make a difference in most admissions, and especially for internationals applying to small LACs.
From what you’ve mentioned, I see your daughter’s admission strengths as full pay, performing arts ECs, international life experience/perspective, notably development economics. On the neutral – or maybe minus – side is being White, Judeo-Christian, upper middle class from the UK. (My assumption here. If I’m wrong you can add any diversity factors to the positive tally.)
Lesser known colleges and those located outside of big cities, especially in the midwest or south don’t attract as many international applicants as schools with global name recognition and/or those located in major cities. If you had more time this trip or if your daughter could make a second trip next spring, then you could consider a wider geographic range, but if that’s not the case you’re better off looking at a broad number of schools within a narrow geographic focus.
As it is, I think you might consider saving Chicago for next year and concentrating on the northeast, from Philadelphia to Maine, especially if you’re thinking about spending time in New York City. Along the way there will be some schools that will appeal to both your daughter and son. In the cities, you could also divide forces and make separate visits.
As the visits progress preferences for urban, suburban, or rural; artsy or sporty; activist, liberal or middle road will emerge and you can recalibrate the list accordingly.
I believe your daughter’s counselor did a good job in helping her craft a cohesive group of LACs (except for Boston College, which seems like an outlier to me). As an under-hooked international, I would plan on applying to 8 to 10 schools, even more if you can visit more. Based on your daughter’s ECs and your visit constraints, my “choose from” list would look something like this. It’s all reaches and matches, but I think she’s in the ballpark for all of them. Her safeties would be in the UK.
For your daughter: Barnard, Bard, Bates, Bowdoin, Brown, Colby, Conn College, Haverford, Skidmore, Smith, Tufts, Vassar, Wesleyan, Williams, Yale
For your son: Brown, Columbia, MIT, Swarthmore, Wesleyan, Williams
@collegemum3717, very well said…an unsaid/ulterior/selfish motive is definitely to spend time with my D&S…it is getting harder and harder to have these kind of trips…so would really want to not waste it through stress etc…something to keep reminding myself all the time…thank you for all the feedback and perspective…
I think we are more or les definite re visiting Maine, Boston, Philly schools…since we need to land at Chicago and fly out of NYC, those get covered as well. Trying to now work on the various excellent suggestions to figure out the exact route / mode of transport. Point well taken re getting the balance right…but still the various credible choices / options takes a bit of digesting
@PurpleTitan, many thanks for the message …kind of my first trip to the US as the previous ones have been on work etc and did not get to see anything much…would be the first time in US for my D&S …so the scenic/doable drives would def be of interest…
Re the US…I think got triggered by several of our American friends…and then has kind of taken on its own momentum…especially because of the interest in LACs…curious to see how we react to the campus visits…
@momrath, hopefully the visits would one way or the other help in the ED decision…nothing like getting into ones preferred school by Dec and then focus on other areas of grade 12 without going through the stress of applications. Clearly not as straight forward as that but one can always dream a bit
I think it would be difficult to make a second college search visit …so we would try and make this count …through a broad-enough but targeted visit…hopefully there will be clarity as we get to sense the campus etc…although realise as mentioned by several posters, that end July might not be the best time to visit campuses. Will certainly look to re-calibrate through the trip as you suggest above…
Many thanks for the suggested list…a number of them has been on our list for a while but a few are new options…will look up…now that am a proud owner of a Fiske guide
@MYOS1634, well noted and thanks much… looking v much forward to the movie now… I think we are likel to visit atleast2 out of the 4 you mention so should be fun
If this is your first trip to the US, be mindful that driving on the right side of the road is going to be stressful / taxing to you, and adjust accordingly in terms of giving yourself extra time, ensuring that you have an awake person to be your navigator and “call” the turns, etc. Depending on your final itinerary, you might think about using Uber in the urban areas.
Though, thinking about it, driving on the other side of the road and even getting a rental car. . . .not sure of difficulties there.
You could look in to a few very long bus trips or tour bus as well (or just a flight, but you’d get more a sense of the country and its scale from a bus/car trip).
I would definitely look in to the university colleges in the Netherlands.
“Because American friends praise it” is a reason, I suppose, but not a very compelling one to spend a lot more money (at least in my eyes).
Add to this…and is affordable for you. Because as noted upstream, you will not be comparing financial aid offers amongst schools if your kiddo applies Early Decision.
If financials are in any way an issue, you need to go for some merit money for both D and S. To do this, focus on schools that (1) give merit money, as they’ll say on their website; and (2) where D or S would be in the top 25% based on the SAT or ACT scores, as you can tell from their “middle 50%” range of scores they self report, greatly increasing the likelihood that D or S get the merit. Some schools simply don’t do merit aid because they have enough “draw” that they don’t need to, or are saving the money for kids who need financial aid. Going for a “reach” school pretty much ensures you won’t get merit aid. Use College Confidential to see what folks are saying about the merit awards they received. Without merit aid from a US school, your UK unis are going to be the value decision. Be aware that the Net Price Calculator that all US schools are required by law to have on their web page can be extremely accurate (Vanderbilt (TN)) to horrid (American (DC)).
Based on your general route (Chicago to East Coast), think about Lake Forest (IL), Kalamazoo (MI), Dennison (OH), and Lafayette (PA). All give merit aid. You may also want to add in Beloit (WI, just over IL line), Dickenson (PA) and Wooster (OH). Ohio and Pennsylvania are chock full of good LACs for some reason.
I’d also propose the idea of some southern schools. Generally, once you get beyond the Northeast, merit aid increases. DD is at Tulane(LA), and we’ve looked at Alabama, Rhodes(TN), Trinity(TX), Richmond(VA), and considered SMU(TX), Centre(KY), Washington & Lee (VA).
Keep in mind when traveling within the US, you can book one way tickets on Southwest Airlines for pretty cheap (Chicago to New Orleans is about $119 one way).
And go to a baseball game and enjoy an ice cold beer.
American beer is going to taste very bad to Brits and baseball is very slow and boring when you don’t know what’s going on. Just sayin’ 
For a cultural experience, they can stop and see ifone of the D1 colleges’ football team is practicing already + add a little league match with hotdogs and Budweiser from a cooler. Cheaper, culturally appropriate, and you can leave whenever with no regrets. You can even catch several depending on location.
(Most athletes at D1/D2 schools will be on campus in August if not July, even if the only pro sports will be baseball. College sports are a big deal in the US and visiting their facilities is likely to be interesting, too. Some of these D1 teams have equipment as good as professional D1 clubs in Europe.)