Sylvia is a great host. She was easy to get hold of and gave detailed instructions for checking in. Be sure to ask her about the back driveway, so that you don't have to lug your suitcase up the front steps. The house is on a hill, so there are two sets of steps to the apartment that's behind her house. There is a nice kitchenette supplied with cooking equipment. The bedroom and bathroom are both good size. The bed is very comfortable and the whole place was clean.
The apartment is in a very safe area of D.C. where a number of embassies are located. It's a short walk to the Marriott and the Omni if you're going to a conference there. The Metro stop is a short walk and there are some nice restaurants nearby. I would definitely stay there again.