What a treat to get a sneak peak into the 2-3 flats in Dupont Circle! Although Greg's vintage place was built in the 1800's, it was very clean (not a speck of dust) and comfortable (if you're sensitive to older homes you may want to reconsider if it's the right fit for you). Definitely big enough for the 3 adults and a newborn in our party. We greatly appreciate how thoughtful the unit is organized and kept. From all of the baby tools you might need to a hair dryer, Greg made staying there very easy with his little notes everywhere (the answers to your questions were always right in front of you.
The neighborhood is quiet and within blocks of the Metro (and coffee shops/restaurants). The train or an Uber ($8-12...more during rush hour) is most ideal for reaching the historic sites (about 20-minute walk to the White House....45 minutes to the Capital). Greg was very responsive and flexible with the check-in and check-out. At one point, the toliet wouldn't stop running but he fixed it quickly. The shower water was always hot and the central air was always cold...very important in our consideration for this place. We had a blast!