I'll second Salem for a sailing destination. If you are at all interested in traditional sailing and maritime history this is a great place. You can get a ride on the Fame (War of 1812 privateer replica), take a tour of the Friendship (replica of an east inidaman from the late 1800's) if she is still in port, the Salem maritime museum and the Peabody Essex Museum. There are no shortage of great places to eat for a variety of cuisines. You can take the commuter rail from North Station in Boston and be there about 30 minutes. Then you can walk from the train station to any of the interesting areas.
I lived there about 10 years ago and went back for a few days this summer. Just like I remember it but a little bit nicer.