When I first heard about Joe's disappearance and the subsequent search efforts I was picturing very rugged terrain with towering cliffs and steep precipices along their running route where one might have easily slipped and fallen. IMO after having viewed Google maps of RTR and Fdr 250, I didn't really see any areas where one might have fallen any great distance.
https://www.google.com/maps/place/R...0x871622e0b4193c63:0x41246b3161289ef9!6m1!1e1 However, these images were satellite images and not street views, so it's difficult to get any real sense of the topography.
If, however, he became disoriented and wandered away from the road and into the forest he might have been tempted to climb to one of the higher elevations to get a better view to reorient himself. In this case, I could definitely envision a fall.
I wonder if venomous snakes are prevalent in the area? It's one possible hazard that Joe could have encountered that I haven't heard mentioned previously.