My wife and I stayed in Helen's house for two nights and the experience was absolutely pleasant.
Helen met us friendly, showed the house patiently and explained all the conveniences it has. Moreover, she gave us some advice and ideas to explore the city and recommended restaurants and shops in Jamaica Plain. Helen was always willing to solve any problem or give more information if needed, which was very easy as she lives downstairs. Helen was extremely respectful and let us enjoy our privacy, however it was easy to communicate with her before and during our stay. Each day in the morning, she kindly brought up some delicious bakery, fruit, juice and dairy.
As for the apartment, it is upstairs in a house which is located in a quiet neighborhood at about 30 minutes by subway from Downtown Boston, not far from restaurants and shops on foot. It is luminous, fresh, cool, colourful, very well decorated with taste. The kitchen has all the amenities anyone might need (microwave, toaster, cutlery, oven...) and much space. Thanks to the fan in the kitchen and the A/C in the bedroom, it was easy to stay fresh during our stay. The bed and linen were comfortable so we could sleep well.
I strongly recommend this choice in Boston!