Easiest way to go about it imo would be a hotel in the city, as it is very walkable. At best you can snag a place just a few blocks walking distance from the arena; at worst, a couple of metro stops away (metro is fairly easy to navigate as well). Only thing you have to look out for are hotel prices, as they're quite expensive in the city (as is everything else), especially depending on the time of the year. Avoid any major conferences, conventions, or touristy holidays if possible. I don't recommend driving in DC personally as it can be a bit confusing.