It seems that many visitors to Acadia limit themselves to coming during the summer months - July & August typically considered the "peak season". What most folks don't realize is that there are many things to do in the Fall and early Winter as well.
Acadia National Park is much less crowded in late September through November and a lot of the restaurants & lodgings are still open. In fact, several of the cruise ships come to Bar Harbor in the Fall to see the foliage changing, enjoy the continued temperate climate and hike the trails to see the spectacular views. You can rent bikes to ride the carriage paths, or grab a kayak to navigate around the Porcupine Islands in the crisp New England air.
Personally, I like to go all year round and in the dead of winter, with much of the Park Loop Road closed to vehicular traffic, you can't beat cross country skiing past Sand Beach
and on down towards Thunder Hole (even though this short piece of the Loop Rd is open to cars, there aren't that many). I've been in the Park in February and not seen another soul - it's like having a private refuge full of spectacular scenery all to myself!
Unfortunately, I can tell by the drop-off in the number of visitors to the Acadia Vacation Planner website (www.acadiavacationplanner.com) in the winter months, that so many people think of Maine as a summer only destination. Nothing can be farther from the truth, as far as I'm concerned. So don't follow the masses... consider a trip in the off season! The GPS system can take you to these hidden gems in your car, or on foot. Check the Maps and get cracking at enjoying Acadia all year round!
Jeff