I live in Maine and we go camp in the state quite a bit. You have already gotten some good advice, and like GreggH said, if you limit yourself to ONLY full hookups you will miss some of the best places in the state.
There are plenty of very nice places just water and electric and some with no hookups at all. I would recommend staying at some of those in addition to the full hookup sites.
If you look at this thread, http://www.airforums.com/forums/f42/...ns-112554.html
I and others listed a bunch of places.
In my opinion Blackwoods campground is the nicest campground in Acadia (and Bar Harbor) but no hookups so not a good option for long term. All the other campgrounds have very little to no privacy and some have hardly any trees so it's hard to recommend any. Having said that when we do stay in Acadia and want hookups we stay at Hadley point.
Besides the recommendations I already listed in the thread above, I would highly recommend Coobscook State park. Probably the most beautiful campground in Maine. But again no hookups. Same goes with Lilly Bay State park at Moosehead Lake.
If you are going to PEI I recommend bringing the camper. It is LONG distance away from Maine. There are some B&Bs to stay at, but I personally would prefer to bring my AS.
If you have any other specific questions, feel free to message me directly.