Claire,
I recommend getting far away from the airport to avoid rush hour I 495 on Friday morning.

Suggestion: Do a mapquest from Dulles (IAD) to West River MD. Along the route will be College Park MD, where there are several motels just off I495. Mudcatters have stayed their successfully, you might PM KT above for the name of the specific motel where they stayed.
and/or
Do an www.orbitz.com search for motels in College Park and note their proximity to I495. This will have you on your route to the Getaway.

you can PM me with questions.