short review: this unit is excellent and Tim is a fantastic host, if the size and location meet your needs then book it ASAP.
some more details: Tim was incredibly accommodating as our timing was less than ideal and weather had thrown a fairly large wrench into our plans. He was very easy to communicate with before and during the stay and made everything very easy. The space is certainly small, though nothing feels cramped and it is all very nice. The parking is very helpful though it does require a small walk from the alley around to the front of the building. As we stayed from Sunday night into Monday morning, there was quite the hustle and bustle in the morning, so if you're a light sleeper this may pose an issue though it's to be expected in this type of location. Absolutely none of these things should be deal breakers if you plan to book this space for a night out in Boston as the location simply cannot be beat. We are already planning a trip to come back to this spot in warmer weather.