Erin's place is great, clean and very-well furnished. We felt like at home. She lives upstairs, what makes communication very easy.
The apartment is big and we appreciated the well-furnished kitchen, the living-room where our kids played a lot with the provided legos! The bathroom is very nice and both bedrooms are very comfortable.
Erin lent us a stroller (a very nice one) what helped us a lot travelling with our children.
If you walk 10 minutes you' ll reach Central Square Metro station (T) where you are at Harvard's University (guided tours were free thanks coupons we found in the apartment!) in 7 minutes. Boston's center is also in 10-15 minutes in T.
Cambridge is very pretty and we loved Boston!