Our stay in Betsy house was wonderful. First the apartment is so nice, and there is pretty much everything you may need (with a special mention for the kitchen !) and it's about 15 minutes walking (for slow walker, 10 if you walk at a regular speed) to the center of Boston. Betsy was really nice to us too, she was available (even if she had to go out of town for few days she always reply to our questions within a day).
We would definitely recommend our family and friends to stay at her place if they plan to go to Boston !