I stayed at Barbara's place with my fiance and both sets of our parents, so six adults in all. We had more than enough space for our stay; we had a small family reunion with some of our family members in the area and even with around a dozen people, it still was very spacious and great for visiting and hosting! The kitchen has a lot of tools, spices, and other appliances to use and we made use out of the grill twice. Barbara also provided some welcome snacks and drinks, which was a nice touch.
Unfortunately, there is no central air (as is common with a lot of NE homes) and it was in the 90s for two of the days we were there, so it was fairly uncomfortable in the living area where my fiance and I were sleeping, but both bedrooms have window AC units and were very comfortable. If you are staying here during the spring, fall, or winter (or even most weeks in summer), I don't think you would have this issue - especially if no one is sleeping in the living room.
The only real complaints we had with the AirBNB was that it was not as private as we anticipated. The washer/dryer is shared and we had some issues with waiting to wash our clothes as it was being used (and then someone left their wet clothes in the washer overnight so we had to wait until late the next day). Additionally, at one point the six of us were sightseeing while my brother (who lives in the area) was at the AirBNB and Barbara walked into the AirBNB without telling any of us ahead of time or even knocking (presumably because our cars were gone and she assumed no one was there). This was a little alarming to all of us as we assumed no one else would be entering or using the space while we were there - certainly not without advance notice. Needless to say, the rest of the time we were there we took great caution to hide our valuables as we did not know who else may have access to the unit.
All in all, it is a lovely home with a very convenient location to the commuter rail and a lot of space and amenities. Barbara was very responsive to advance questions and let us check in early and provided everything we needed for a mostly comfortable trip. However, there were a few things that were a little disconcerting and I do not think we will stay here the next time we visit Boston.