I just did an exploratory ride down to Lorton from Crystal City yesterday and I decided to follow US Bike Route 1… it uses the MVT and then the Mount Vernon Parkway, then they decide to throw you to the wolves, sharks (WITH laserbeams), bears, and tigers by having you ride down Route 1 for a few miles.
It’s fricking insane! There’s NO shoulder, speed limit is 50 I think, and the road condition is terrible making for a hair raising, white knuckled bumpy ride all the way through Ft. Belvoir. Anyone who calls this a bike route is an idiot and should be embarrassed. I use a helmet mirror when I know I’m gonna be riding on unfamiliar or busy roads. I was too afraid to check it for fear of hitting a big-ass pothole or rock if I took my eyes off the road, or looking back to see a huge SUV barreling at me going 60 mph.
If you want to survive this trip, take Telegraph Road. It has a bike lane for a couple of miles and the parts that it doesn’t it has turning lanes, shoulder, etc… all giving you the extra room to allow cars to pass pretty safely. I would follow the AC Atlantic Coast route. I rode their route down from Boston last year and I generally felt pretty safe the whole time.