The place we stayed last June is called the Cobblestone Cottage B and B. It is in South Harwich. It's not a place that is walkable to a town, but it is close to stuff; very close to the bike trail, with a spur that takes you into Chatham. It's near Brewster, too. It's on the web.
It's a regular house with an addition that has the B and B rooms. She has a pool, too. Very nice and the breakfasts were great.