My impression from the videos and photos of the descent is that the main difficulty is the tightness of the switchbacks. If you are too long or don't have a tight enough turning radius, you have to do a multipoint turn. With rocks on one side and cliff on the other that can be scary, if not impossible. I'd also want low range to be in full control of movement, even when the road is steep or loose rock.
As a kid I lived in the Andes, and rode in Landrovers on similar roads. Even the short wheelbase ones tended to require multipoint turns, but being in the back of a long wheelbase one was scarier.