Last weekend I was down in Blacksburg, VA so I got to run most of 81 through VA both ways... It's going to be tough managing the caravan given the speeds they run there. The speed limit is 65 most of the way (except for a 55 mph stretch through Harrisonburg) and it's policed pretty heavily. We're definitely going to have to stick to that 65-70 mph range to be safe. There will be some traffic traveling 80+ and it's a big time truck route, so it'll be interesting to see how closely we can stick together.
I figure if we leave Fairfax at around 6am we'll be stopping for lunch somewhere south of Roanoke.