Couple traveling to East Coast, traveling between Mystic, CT to Bar Harbor, Maine. We are looking for suggestions on a central location to stay and go on day trips between them. Or, splitting between two locations for our 7-days.

Welcome to Fodors. We removed the Trip Report flag and added state tags

You should consult Google Maps, or any map at all. It is 6 hours between them, so a place in the middle will have you spending 3 hours each way for a day trip. I would not consider that a day trip.

Acadia National Park is more of a hiking destination (though walking or horse drawn carriages are also a possibility). Among other things, it is famous for its ladder trails, which are not that difficult but still could be a challenge..

Outside of Mystic, I highly recommend the Cliff Walk in Newport. It s a public path between the mansions of Newport and the sea.

What sort of activities are you looking for? Might give us a little more to go on.

Lots of sightseeing, food. The normal tourist stuff.
We are extremely flexible, but like to have a plan.

As shelemm said, the destinations are too far apart for day trips to be practical. As far as the Mystic part of your trip, there's the Seaport for a start. A few miles further up the road is Stonington Borough, which features well-preserved 18th and 19th century houses, and a small battle site from the war of 1812.

If the trip is in the summer, Rhode Island has surf beaches about twenty minutes from Mystic. You could take a day trip out to Block Island. The best restaurant in the area is the Matunuck Oyster Bar. https://rhodyoysters.com. As mentioned above, Newport offers beaches, walks and mansions.

Venturing into Massachusetts you might visit the old whaling port of New Bedford, with its whaling museum.

Maybe that will get you started.

Yes, it will possibly be mid-July, so thanks for the suggestions. We can plan to stay in multiple cities as we travel between and through Mystic to Maine. We've never been to the East Coast, other than NYC, so, we welcome any itinerary for this 7day trip.

7 days is not a lot. You have chosen the two most magnificent sights in the region. So if you have 2 nights Mystic and 3 nights Bar Harbor, you have at most 2 more nights. I would give priority to not only the cliff walk in Newport but also Waterfire in Providence. The summer schedule is not out yet, but it is one of the major arts events in the US:

https://waterfire.org/

Where are you flying into and out?

Well you won't be able to do it all and so you have to set priorities as you can easily spend an entire week focusing on Mystic, Newport, Providence and so on. You can spend a week just in Boston or Boston and the historic sites outside of Boston or Boston and Cape Ann, or southern Maine and save Acadia for another trip. Newport in July will be high season and pricey.

Check Acadia National Park news for changes due to budget cuts. Back in 1997 we did a family trip and our son biked up Cadillac and enjoyed riding around. Years later he took his family and did not like how crowded Cadillac had become. He hates crowds, last May we rented a cottage in Surry near Ellsworth and had our son and grandson join us for Memorial day weekend. I chartered a fishing boat since our young grandson is crazy about fishing, it was a best ever trip. We are doing something similar this June on a long weekend staing at a VRBO place near Portland. This gives us one day to go up to Boothbay area for Maine Coastal gardens, a day of fishing and then stopping at a classic car show in York on our way home. I suggested to our son that they coukd take boat trip to Monhegan Island for some good hiking and no crowds. They can also do bike trails in Portland.

We live in NH and do not care for crowds in southern Maine but there is a lot to see and do innthe mid coast area. You can download a list of conservation areas in Harpswell area, do some hiking, eat lots of lobster. The Maritime Museum in Bath does some lighthouse viewing cruises and even the harvor area is fascinating because of the Bath Iron Works ship building. Bath does a terrific Heritage Days celebration which includes a 4th of July parade.
if you like boat trips, Portland Maine's Mailboat visits the islands in Casco Bay. Not a lot of narration but some.
it really depends onmyour style of traveling. Although we avoid Camden it was still a place for an interesting garden tour and we like takingmthe auto road to the top of Mt. Battie where we sit in bag chairs to enjoy the view and take an iced tea break.
in the Rockland area there's the Farnsworth art museum and further east, the Owls Head car museum and no long lines at our favorite lobster shack. I like the car museum better for weekend special events like the weekend we saw antique airplanes flying and a restored Lombard log hauler.

due to distance, I agree that Bar Harbor might he better saved for another trip or at least avoid visiting when cruise ships are docked.