Check out Cottonweeds in Freeport, ME. I love that shop. Hit Marden's in Scarborough near the South Portland line for great deals on fabric (4.99 a yard and sometimes less). Quilting by the Sea in Trenton (on the way to Mt. Desert) and another Marden's in Ellsworth before Trenton.
Looking forward to other suggestions!
Oh, and the Maine Quilt Show is at the end of July. Also, a nice, little show in Bridgton, Maine in July but that would probably be out of your way.