The missus and I went a few years ago. Stayed in the Back Bay area at what is now the Loews Boston. It's the old Boston Police Headquarters. It was pretty nice. From there, we walked to the Boston Common, the Freedom Trail stuff, the State House, the North End, across the river to Bunker Hill, etc. We took the subway to Cambridge, to Fenway Park and to the JFK Library. Never needed a car.
Had some great food and every other doorway in Boston is a bar. Lunch at the Union Oyster House is a must, and we had a fabulous Italian dinner at Maurizio's in the North End (what others are calling Little Italy).