Originally Posted by Traveller
If you rent a car, IMO, this is the easiest airport to use since the Dulles access road has little traffic on it.
True, but the Beltway is usually jammed during daylight hours going across the American Legion Bridge from Virginia to Maryland. Because of this, I'd recommend DCA or BWI for easiest access to Rockville, unless you're heading to/from Dulles during off hours.