In Boston, I would go to see the USS Constitution which is docked in the Charlestown Navy Yard. It is a very interesting look at what being a sailor on a sailing ship was all about in the 19th Century. The ship is still a commissioned vessel of the US Navy.
You can also walk the Freedom Trail. If you go to the Boston Common there is a booth there that gives out information. Walking the trail is free. I think the USS Constitution might be free, too.
If you don't feel like doing the whole Freedom Trail, go to the North End and see Paul Revere's House and the Old North Church. The North End is home to the Italian community and there are lots of good Italian restaurants there.
You can also go to Fanieul Hall which is where people like John Adams and other fathers of our country from Massachusetts gave speeches. You might also want to take in the Quincy Market which also is very close to the North End.
If you are there on a Friday or a Saturday, walk through the open air peddler's market at Haymarket where they sell fruits and vegetables, fish and meat.