Look in the Bar Harbor Mount Desert Island area. Lots to do there and Acadia National Park is on the Island. The Park Loop drive includes a drive to the summit of Cadillac Mountain. If you go there at sunrise in the autumn you can be the first to see the sun rise over the continental USA.
Bar Harbor is a pretty cool town and a good place for celebrity sightings. The small local airport has the most private jets parked there you are likely to ever see in such a small airport.
There are plenty of camping choices including ocean front or lake front sites. Oceanside KOA and Narrows Too are adult orientated with sites right on the ocean. Both are pricy but worth it. Biggest difference is Narrows Too sites are larger and more private and are full service but KOA Oceanside has better sunsets.
Bar Harbor Campground, Headley's Point and Mount Desert Camping are more kid friendly and still offer ocean front/view sites.
If you want a true beach vacation then Old Orchard beach in southern Maine is the place to be. Miles of fine sand, bearable water temperatures and crowds.
In Old Orchard try Bailey's, Paradise Pond, Wagon Wheel or many others. If you plan to stay in Old Orchard beach in July or August make reservations at least 4 weeks in advance. They have a permanent mid-way set up on the beach, fireworks every Thursday night, tacky beer bars and junk stores galore. Tacky as it is it has a certain charm and is relaxing in a weird way.
Bailey's is our favorite when in Old Orchard. It has a big rig section which includes an adult only pool with a bar and restaurant in the pool area (strictly enforced). It's not the kids that bother us, it's the loud yelling parents. No parent's screaming at their kids is a luxury beyond words!
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