I can't hang with the Saturday ride because I'm not fast enough, but I got the cue sheet from them last year and I do it on my own. Actually I modified it a bit so I do my own 24-mile version of it. I use it as my training loop when I have to do long rides by myself. It starts briefly on trails -- west on the WOD and south on the Ffx County Pkwy trail to cross over the toll road. Then it heads south-ish through various residential neighborhoods into Herndon and I think Oakton, too, before circling back up to Reston.