All good suggestions so far teddy. It's true about the size of the mosquito..... there's debate now in the legislature on whether or not to make it the state bird! And yes, you'll only be half way up the State of Maine! Not in the true northern Maine counties, which would be an additional 6-7 hours drive further!!!
As the resident Pixie Mainiac (what tourists usually call us Mainah's) a care package will soon be on it's way to you.
Bar Harbor, Acadia National Park, Northeast Hbr, Rockerfellers, carriage trails for mountain biking, hiking or horseback are all in your backyard. Please don't let the fact that occasional outsider Martha Stewart has a place near you keep you away! There's also THE CAT.... a jet powered katermaran that makes daily trips to Nova Scotia..
We've taken day sails out of Camden & Rockland & Boothbay.... we go to Boothbay almost every weekend in the summer and have wine & cheese on the rocks and watch the sailboats sail into harbor.... regulars include Walter Cronkite & Ted Kennedy (who manages to often run into other boats!
You may opt to leave the quiet of Mount Desert Island early on your last day and hit Boothbay on your way home and Old Orchard Beach would be a good stop also for the kids. It has the rides & games for the younguns but more importantly, it has a long sandy beach prob. 3/4 mile long to walk and water warm enough to stay in.....
On your way up, if you choose to stop in for a pee break, I'll take you all to the most photographed lighthouse in America, commissioned by George Washington!
Most of all, Have Phun! and enjoy our great state and leave as many tourists dollars as you can!!