I don’t think there are any accommodations, hotel or Airbnb, better located in all Boston. Everything is walking distance and should you want to go further, metro is about 250m away.
Appartement was perfect for a party of 4 (including 2 teenagers).
Very good communication before and during the stay.
To be fair, there’s only one downfall: parking. It’s Boston after all. Went to a public one about 10 minutes walk from there.