My understanding is there is good whale watching from spring until October in Maine.
We’re heading to Maine (my favorite place on the planet) next week to stay with old friends at their island cottage, no cars just docks and pines and peace. Best part is we’re picking up ChoatieLt on our way up and he’s coming back home with us for a week before school starts.
Anyway, I love all of these timely suggestions, too, many of which we have yet to do. Thanks, @inthegarden for starting this thread. 
@inthegarden Kennebunk/Kennubunkport are about 30+ mins south of Portland.
Have a great time!
If I was traveling to Maine and I had lots of time, I’d also visit Jackman/Greenville area (Western slope area); Lubec/Eastport/Calais area (very downeast…up coast); Baxter State Park; Monhegan/Vinalhaven/Northhaven/Islesboro…or some island; an agricultural fair; the Maine Music Theater or Ogunquit Playhouse; Acadia; the coastal towns; etc… There’s a lot to do here as there is in every State.
We are heading to Bar Harbor again this year (probably the 4th trip in the past 6 years). We spend the night in Boston (where my daughter lives) and then do the drive to Bar Harbor starting fresh in the morning. We stop in Freeport (LL Bean has clean bathrooms), have lobster rolls for lunch and walk the stores to take a break from driving. We love Arcadia and stay in a nice place right at the harbor in Bar Harbor (yes one of those $4-500 a night places). One of the benefits of that is the ability to walk around downtown any time of day and enjoy the stores and sites.
I have gotten good recommendations from the Maine natives on CC - places to eat and stop at. We have stopped in both Kenneybunkport and Portland over the years.
We usually spend 3 nights in Bar Harbor and one of those days is spent in Arcadia (start out early in the morning at the beautiful beach in the park and then work our way to the top of the mountain- by car). There is plenty to do to keep you busy for several days both in Bar Harbor, Arcadia, and some of the other cute towns on the south side of the island.
@intthegarden: Given your screen name, I assume you enjoy gardens–both Asticou and Thuya are lovely. Even more spectacular is the Abby Aldrich Rockefeller Garden in Seal Harbor (designed by Beatrix Farrand, a celebrated landscape architect who also designed Dumbarton Oaks.) You’ll need a reservation to tour the Rockefeller Garden, which you can do it online (https://www.gardenpreserve.org). All three of the gardens are managed by the Land and Garden Preserve.
In Freeport, I recommend you eat in
Bucks naked BBQ , I love “the bucket”, I change the chicken for more sliced brisket, is awesome.
568 US-1, Freeport, ME 04032.
In Augusta, capital of Maine, a nice and unexpensive place to stay is Hotel Senator inn and spa, I’m not sure if it’s booked.
Enjoy your trip.
I feel like I’m vacationing just by reading this thread.
This is a trip I’ve always wanted to take. I want to stay in ALL the lodgings suggested and linked above!
I’ve been out all day (in this heat wave, whew!) and I’m just overwhelmed by all your responses! Don’t have time (yet) to respond and thank you all individually, but a BIG THANKS to everyone now!! Glad some of you are along for the ride whether on memory lane, embarking to Maine too, or just wishful thinking (for now).
On tripadvisor, I see a lot of the accomodations are going FAST. Maybe I should also check out AirBnB (never done that) and I’m also looking into your inn suggestions. I’m going to try to nail down as much as possible tonight/tomorrow while there’s still some choice. So if I’m not posting a lot, it’s because I’m furiously looking into options and making decisions but I’m definitely checking into CC to read your suggestions.
So, If I’m reading this correctly, Route 1 is slow and jam-packed with traffic (and places to stop) but from a logistical standpoint it’s doable (with time for some stops) to drive on Route 1 from Portland to Bar Harbor in two days, with a stop somewhere in the middle. Hard to estimate driving conditions on different sections of the road, but would you say that Camden/Rockport area would be the logical half-way point (in terms of driving time, not necessarily mileage) or would it make more sense to stop further south (Booth Bay or Wiscassette areas) and do the rest the next day. Or stop two nights in between (but less time in Acadia/Bar Harbor?) I’m feeling nostalgic right now for the spontaneous days of my youth when I never reserved anything at all. ARRGH! (But it’s a great privilige to have this problem …)
10000 French citizens left the Acadia region following the French and English conflict in Quebec. These migrants made their way to New Orleans. When they introduced themselves to the locals as Acadians their French accent to them sounded more like A Cajun. Now the French Cajuns of Louisiana.
Now you you know the rest of the story. :-c
Be sure and check Bookings.com.
They have rooms sometimes you do not see on the hotel website.
Also ALWAYS book directly with the accommodations (unless it is Bookings).
You get better service and they prefer it. We often telephone when nothing shows on their website and
many times they do have a room. We also call just to make out special requests (high floor, not near elevators, etc.)
Many of the accommodations in Iceland (little towns) only use bookings or a call.
H managed his reservations in India through them or emailing the place.
Just being able to sleep with the windows open is a treat! We can’t do that at our apartment in Asia, too noisy and too humid.
For me I say spend more time in Bar Harbor and just drive 95/295 from portland and it takes 3 hours. We did the route 1 drive once and overnighted in Rockport and decided it wasn’t worth it.
If you open the windows the birds and peepers at night and in the morning with your coffee will be a symphony!
@kiddie, how is the traffic on 95/295? I’m not crazy about high speeds + a lot of traffic, though I’ll do it if I have to. Coming from Boston, though, probably any other drive looks easy to you, right 
?
If you want to see one of the Maine colleges I would pick Bowdoin - that way you get a great little town plus a pretty college!
95/295 is fine - lots of it is straight and you don’t have to drive fast. We have never hit bad traffic on it (although one year there were work cones on the shoulder for almost all of the ride and we joked that they had taken every cone in the country and used it for that stretch of road.) We have hit traffic in New Hampshire and of course entering or exiting Boston. The drive right outside of Bar Harbor to get onto Mt. Desert Island can be slow (one lane in places) but that is the only way in or out so you have no choice.
The highway traffic is worse on Fridays and Sundays in Maine, and heading from Portland south to Boston on a Sunday is a slow go, lots of traffic along the Mane and NH beach exits.
I like the coast of Mane, but I like the mountains of Maine even more.
Good to know about Fridays and Sundays, @RightCoaster. That makes sense, and I’Il plan accordingly. Since we Fly out early Monday I’ll make a point to head back to (or near) Portland by Saturday.
Maine mountains will have to be another trip (and Vermont and New Hampshire as well!) We live in mountains (central Appalachians) so we’re feeling the pull of that rocky coast.
A few restaurant recommendations for the Bar Harbor area:
Trenton Bridge Lobster Pound in Trenton, right on the way to Bar Harbor. Rustic but really good.
Beal’s in Southwest Harbor, which is a small town on Mt Desert Island. It’s fun to drive around the island. Beal’s has lots of non-seafood items as well.
Both places have websites.
Also consider State of Maine Tourist Bureau approved lodging - https://www.mainetourism.com/hotels-and-lodging/ .
Acadia is nice, but the heart and soul of Maine’s coast is found in the small towns which pop up along our narrow roads away from the popular spots. Maine’s island communities are truly unique. And there are thousand of ships from away which spend Maine summers away from the congested areas. You really can’t miss if you pick a random place and just go there.