The guesthouse (Cardozo Guesthouse) is located just off U St - the location is lively. Restaurants are open in the evenings and people are walking around, as opposed to more empty areas near the mall. The guesthouse is just a couple minutes from a subway station & bus stops, although I found that walking (when possible) was usually more reliable.
I stayed in the Pembroke room, which is directly up the stairs when you walk into the house. It's right next to the shared bathroom, which was convenient. I saw other guests just a couple times and the bathroom was always free when I needed to use it. The listing was accurate - the room had a mini-fridge, iron, hairdryer, etc. AC worked great and I felt pretty relaxed during my nights.
Although I didn't meet Kathleen in person to check in (the guesthouse is fairly self-hosted) Kathleen responded quickly to my questions. I was able to drop my luggage off early, as well as come back for it later during checkout.