Hotel
For our out of town guests, the DoubleTree in McLean Tysons is about midway between Potomac, MD (church location) and Fairfax, VA. It's also a 25 minute drive from Ronald Reagan National Airport (DCA) or a 20 minute drive from Dulles International Airport (IAD). The location is conveniently located near restaurants, shops, grocery stores, and whatever else you might need during your stay. Note that self parking is $10/night.
Hotel
The Hilton Garden Inn is very close to the DoubleTree. Note that self parking is $6/night.