Walk 10 minutes to hiking trails, or drive (or take a free bus) around Mt. Dessert Island where you can stop to hike up mountains, swim in lakes, view the rocky coast, or visit Thunder Hole.
You can hike (or drive) up Cadillac Mountain, the highest mountain in Acadia National park, is one of dozens of mountains to climb. From here you can look down to Bar Harbor and the Porcupine Islands, the Cranberry Islands, and much of Mt. Desert Island. Hike the many trails around the island. A map may be obtained at the part Visitor Center.
Other activities include horse-drawn carriage rides, sailing, fishing, golfing, birdwatching, shopping, ocean cruises, and eating at many of the fine restaurants. Some additional great spots are Pretty Marsh, Echo Lake (beach area for children), Sand Beach on the Atlantic Ocean, and Somes Sound, which is the deepest fjord on the east coast.