If the younger members of the family are getting restless, take them to Coastal Childrens Museum. With lots of interactive displays and exhibits, this attraction makes learning fun.
You'll have no end of sightseeing choices when staying in Rockland. Coastal Children's Museum is an ideal place to kick off here, but there are plenty of other fine places to experience. Samoset Resort Golf Course, Maine Lighthouse Museum, and Rockland Breakwater Lighthouse are close to the interactive exhibit for kids and and will cap off your day nicely.