The thing I can't figure out is why he'd walk back around behind the RV instead of simply waiting for it to drive away and starting from where he got out.
Unless... if you turn on satellite view, is the spot where he gets out grassy or sloped in a way that would make it difficult to run? Then he might go back behind the RV to get back onto the road to run.
Wasn't there a bike on the trip? Which would explain Day 1 speeds... Anyway, I recall in the blog they talked about biking with Rob. So is it feasible that rob and one of the crew exit and go to the back to grab the bike? Unless they kept bike inside the RV, then this bike theory is bunk. I'm sure ESPN will have some footage since they hung out for days with the RY gang.