The Renaissance Boston Water Front is in the new Seaport district. If you are planning on a location near all the Boston sights, I will not stay there.
It may be a 15-20 min walk into Boston if you walk, along the way you will pass by the "subway station" for the Silverline, which is really a bus.
Don't get me wrong, it is a great new location for the harbor view, but besides restaurants around the hotel, there isn't much there.