Also recommend against an RV since you said you were doing Zion, Bryce, and Arches. Some of the really scenic roads are white-knuckle drives in a car.
Northern Michigan is really stellar. Traverse City, Sleeping Bear Dunes - actually all the Lake Michigan coast. You could take the ferry from Michigan to Wisconsin and then down to Chicago.
http://www.lake-express.com/
https://www.ssbadger.com/
Have others taken an extended road trip without reserving places to stay in advance? I’ve only done that once, on a two-week trip, and it was a complete and total nightmare. I vowed never to do it again. This was pre-Internet, however, and I’m pretty picky about where I like to stay.
Coming up with a plan for the most popular destinations might be a good idea, If you have any desire to stay in the iconic lodges in the national parks, advance planning is definitely a must.
But I’m curious to hear if others have successfully done road trips without advance reservations.
Cleveland has the Cuyahoga Valley National Park. Was there this weekend. 
@notelling, I often travel (including a cross country trip and foreign trips) where I only book a day or two ahead. I’m fairly picky about accommodations especially on cleanliness more than amenities. I like the flexibility of not being locked in on a road trip. Internet resources do make it easier to plan on the fly.
I have only stayed in National Parks with advanced reservations. Generally, they try to stay at capacity most of the year, so openings at the last minute IN parks are very difficult to get. I know that’s not nearly as spontaneous, but it’s the tradeoff for staying IN vs near the parks. We are somewhat particular about lodging–preferring nonsmoking facilities and in or as near as possible to what we are there to enjoy.
Here is a link to an interactive map of all National Parks and the shortest route between them. It doesn’t include any “national historical parks”, or just plain “parks” that are run by the NPS (like Great Falls or the Statue of Liberty).
And the UNESCO sites are an interesting mixture of natural and historical;
Thanks for the info!
I love that map! Makes me want to start planning a trip!
Are you still trying for the NW?
I would have to modify it somewhat. For example, the map does’t include rt 101 in the Pacific northwest. I don’t think we’re going through California. We also want to hit some cities such as Chicago, Seattle, Portland, New Orleans, Austin, Charleston, Savannah and maybe Miami if we get to Florida. Some of these places will probably be only a day or two. Not having been to Chicago, I don’t know how different it is from NYC. Since we live 75 miles from NYC, we’ve been there many times.
If you’re going to go as far as Miami, consider going a bit farther to Key West.
I’m making your trip longer. 
We were also planning on Key West if we go to Florida.
Great minds think alike – Greenwitch posted that map in post #46! Great map!
Oops! Sorry for the repeat. Would love to attempt it someday.
I would Love to make this trip. I plan to buy a cargo van and outfit it as a stealth camper van - simple fan, no propane, well-insulated, home built. Five more years of working…and then!
You can take a ferry across Lake Michigan from midway on the Michigan west shore to Milwaukee then drive down to Chicago. Not sure when the ferry cuts off for the season, however.
Looks like October 16th.
http://www.ssbadger.com/schedule-fares/