Went to Maine last year and stayed right off MDI in Trenton, ME. It was amazing, right on the bay. I loved wearing sweatshirts at night and no a/c really necessary. We actually ate lobster so often that I got tired of it.
I remember looking at Down East magazine and they had a lot of ads for Maine camp/resorts. I also bookmarked this place --
http://www.migis.com Looks beautiful.