Hmmm, while 55 miles is fine with me, I hate to see someone discouraged because of distance! Is there a shorter route we could all agree on? I remember some of those loops around Warrenton as being fairly hilly, which would be a challenging 55 miles for someone not conditioned to the distance.
I'm not as familiar with the Virginia countryside (even though I'm from VA), I ride more in southern Maryland. I do have a nice ride out of the Davidsonville, MD park n' ride, which I believe is a 40 miler, though there are no real hills to speak of.
But, I'm up for almost anything, happy to follow the leader!