Check out this website...
http://www.cityofboston.gov/visitors/default.asp
I am from the Boston area...Fanueil Hall Marketplace, aka Quincy Market, is a nice take in close to the pier, as is the Aquarium....the swanboats, in Boaton Common, is good if you have kids....
In St Johns, we did the Bay of Fundy tour, and, shopped the area, by the port....a very friendly city....Have fun!