We took a spontaneous boat trip around Boston harbour. We had a perfect day, not too cool, and with clear blue skies. On the boat we were regaled with tales of the heroic Yankees (Hooray!) versus the dastardly British (Boo!)
The main stopping-off point is the USS Constitution, the oldest comissioned boat in the world. In order to maintain this status she has to sail a short cruise and carry out a gun drill each year. The museum alongside details the history of the naval docks there, and in particular of rope-making, the docks supplying the rope for all of the US navy for a number of years.
Boston is kind to the pedestrian tourist; you can walk everywhere and the city centre is not too big. There are plenty of historic buildings, and Quincy Market, although a bit touristy, is still worth a visit. We were lucky with the weather: the great wave of cold that is dumping the snow we're seeing on the news arrived about 12 hours after our departure.