Portland Museum of Art has some good stuff most of the time.
If you like Maine coast painting, Edward Hopper exhibit going on at Bowdoin College.
Colby College in Waterville has:
Photography Dominates Colby College Museum of Art This Summer
Photography from various periods in American history comes together in separate but related exhibitions at the Colby College Museum of Art this summer. American Modern showcases photographs from the 1930s by American masters Berenice Abbott, Margaret Bourke-White, and Walker Evans with loans from major collections including the Metropolitan Museum, the National Gallery of Art, and the Art Institute of Chicago. Recent photographs by Andrew Moore illustrate Detroitís challenges, and a selection of works from a recent gift highlights images by notable photographers such as Berenice Abbott and Ansel Adams. Also on view will be a selection of prints by James McNeill Whistler, presented in honor of the late curator and print scholar David P. Becker.
Check out this in the little town of Georgetown (A nice place to stop and photograph as well!)
Georgetown Goes Modern: The Modern Art Movement Meets An Island Community
Opening Reception - Saturday, June 25, 3-5PM
Exhibit runs June 26 - September 10
Georgetown Historical Society
GHS presents a uniquely close-to-home perspective of how our island community offered shelter, sustenance, and inspiration to artists of the American modern art movement in the first half of the 20th century. The exhibit will include dozens of paintings, photographs, sculptures, and artifacts from Day, Ipcar, Kaisebier, Lachaise, Levine, Pucci, Schoener, Stieglitz, Strand, White, and the Zorachs. The close, interdependent relationships among the artists, as well as between the artists and this islandís residents can be seen and felt in the works they created and the lives they led.
Heading up the coast...
For galleries, the area around Rockland is full of them. Thomaston; check out the Haynes gallery on Route-1. In Rockland, just walk the downtown area checking out the bunch. The Farnsworth museum has a Paul Caponigro exhibit going (Nice B&W stuff). Too many Rockland galleries to name, but they are all within a half mile around the Farnsworth.
In Rockport, you may want to visit the center for maine contemporary art, Peter Ralston's gallery (a local tireless photographer of island scenes), and the Maine Media Workshop's gallery.
The whole Rockland/Rockport/Camden area is dripping in photography. It's a beautiful area that has attracted a history of famous artists, but it's also got a history as a center for learning for this sort of stuff. We've had the Maine Photo Workshops/ Maine Media workshops going on forever bringing in experts and students from all over the world. We had the short lived Kodak Center for creative imaging which brought also sorts of electronic imaging people into the area. The Farnsworth has been working hard at boosting art activities as well.
In Camden, Tillman Crane has opened a gallery (platinum LF stuff)
Further up, Belfast probably has some galleries, but I'm not familiar with that town.
I'm living right in the middle of all this, and my summer is so busy I can't get to all this stuff. I take photos constantly though and have some at http://jason.philbrook.us/gallery3/index.php/ There are landscapes in there, but it's a mix of everything.
For scenic photography, visit any of the peninsulas or connected islands that head south from Route 1 and get yourself lost. Georgetown, pemaquid, port clyde, As you do downeast, the peninsulas are nice too. Stonington, Cutler, Jonesport, etc.. Along the coast, visit Fort Knox for a mix of scenery, history, and architecture. Every town with a rocky coastline has scenic opportunities you can find just by wandering along the shoreline. You can basically park and walk along the shore and if you respect the property and property owners, you're not going to be chased away. I do this regularly in my hometown of Owls Head.
A ferry ride to one of the Penobscot Bay island is a nice way to spend half a day. Rockland Breakwater and most other lighthouses are nice stops for enjoying ocean scenery or picnicing. The breakwater also has many abstract and people opportunities. Penobscot Bay is the stomping grounds of Eliot Porter for much of his famous color nature work.
A day at Monhegan will also be very productive and you go by islands owned or used by the wyeth artists'.
In Acadia, spend some time going round the island at various times. Get out and hike some too. Lots of stuff you can't see from the car.
Aside from random antique store mini-collections, there aren't camera stores up this way. Bring what supplies you need.