Driving pulling a popup camper. Nope, my family doesn't have the attention for museums (I like them though

), I'd guess that lighthouses fall into that category

. And we don't like crowds or shopping

We love camping, and do a lot of camping around here in Michigan(lots of forest and lakes, campgrounds and canoeing

), but we are trying to figure out what Maine has that Michigan doesn't, since it is a 20 hour drive. The only thing so far is the ocean, and we're trying to figure out if that is worth a 20 hour drive...
My kids really love things in the water. I remember a few trips to WA state on the puget sound (my wife says thats too far right now), and there were awesome tide pools just packed with critters, my kids would go bonkers for that. Does Maine have anything like that?
I read somewhere that the Atlantic ocean is only around 55 - 60 degrees during the summer? Is this true? I suppose that it doesn't matter too much if we could find a nearby inland lake. Freshwater is so much tastier...

I'm pretty clueless about the eastern side of the US....

I did ask for a package from the Maine Chamber of C last year but never received anything...I'll try again this year.
Thanks, Rick