Originally Posted by tazi
My BF just got a 1 day rental from Avis for $14 ... pickup at IAD and return at BWI. Renting a car is definitely the way to go.
If you do rent a car, I would suggest either the Residence Inn or Hampton Inn at Arundel Mills Mall. The car rental facility is about 5 minutes away on Arundel Mills Blvd.
Here's another rental car vote for the OP.