Thought I would try "walking" the road from the ramp area, via Google's little walking guy. I found myself turning left at the corner of Ridge Route and the main road as it was "closer" and there were buildings visible. With a little hike, I wound up at the Shell Station (left side) where all of the truckers pull off and refuel. (In the Google snapshot, a truck from Idaho was right there - funny.). So it is possible that he hitched a ride at the station. Plenty of truckers there, day and night. Here's that view, if interested:
http://goo.gl/3dSYn3 So posting in locations and sites where truckers go might be a great idea. If he hitched a ride with a truck there, it may be in another state, and the driver unaware that this is now a missing person case.... Just postulations, thoughts, my own opinions!