We found a VERY out-of-the-way RV park in Georgetown, ME, Sagadahoc Bay Campground, $48/night.  There are only about 15 sites in the whole park and it's right on the edge of the bay.  What was so incredible about it here is that at low tide, you can literally walk out a mile or more across the entire bay.  We just never experience this to this degree on the west coast.  At high tide we had a nice sandy beach.  Interesting people here and amazing experience walking out on the ocean floor.  In the pictures you can see people out digging for clams.  Today, we are off to Hingham MA where we'll stay and take a ferry into Boston.