The April US CMS meeting will be held on Saturday, April 22 at the Department of Physics at the University of Maryland. April is one of the nicest times of year in the Washington area. You may also consider staying in the College Park area and taking the Metro to the APS meeting.
Hotels are considerably cheaper in the College Park area than in downtown Washington.
Late April and early May is a time when many US High Schools organize senior trips to the Washington Area so try to plan ahead and make reservations early. Parking in the garage is usually free on Saturdays. The Parking Garage is further along Regents Drive opposite the Physics Department. An agenda for the meeting will be sent to you by Thomas Muller.