The Google car passes a red Honda Fit at a relatively wide spot of the outer loop - south side. At this point there's even room to pull off on to the shoulder and view, maybe even turn a truck or RV around. It gets narrower further up, and the side slope steeper. Just judging from the Steetview, it would be best if one or other of passing cars pulled half way off on to the nearest wider shoulder.
Convention is that the downhill car pulls off to let the uphill car pass, but on this road downhill is on the inside, next to the drainage ditch.
In streetview there is a pickup camper in the lower upper lot.