There are a few options on "AirBnB".
For the FWW, I stayed with a family in Wiscasset, right on 27 about 5 miles from the railroad. They have two rooms (front to back) one with a single bed, one with a double. They do have two young boys, but if you can deal with that, it's a place to stay for ~$70/night.
Judy Fossel also rents her converted barn on AirBnB. It appears that it would require a larger group to go in on it together.