I have trikked from Leesburg to Rt 66 in 5/10 mile segments on the Washington & Old Dominion Trail near Washington D.C. I enjoy starting in Vienna and riding to Falls Church, with a few big hills. But a daily ride would be in the Ashburn area. You can jump on in Leesburg, Ashburn or Sterling. The trail is relatively flat and not so crowded during the week. But weekends will be a exercise in keeping to the left and yielding the right of way.
Suggested LodgingKey Bridge Sheraton (May also be a Hilton?)
hot dog & hamburger joint about a mile away from the trail intersection with the Mt. Vernon Trail