Warren Island State Park is located on an island near Islesboro. If your family is comfortable paddling a short distance on open but protected water, this is a trip worth taking. Take the car ferry from Linconville to Isleboro (which may be the most thrilling part of the trip for some kids). Put your canoes in right near the ferry terminal and paddle the 1/2 mile across to Warren Island. The crossing is fairly protected and generally mild, but it's worth understanding winds and tides before heading out. The island is big, with several spread-out campsites along its shores. There's a trail that loops along the shore and back through the center of the island. During our trip we found a nice stash of board games, outdoor toys, and crab-catching nets available for anyone to use. There's also an on-site ranger most of the time. We did this with kids ages 4 to 12.