There's no "long haul" out there. I've never been in that part of the park, but from looking at the map I would say the only likely survival there would be to hunker down and push the button (the backcountry equivalent to calling 911--not an option back then.)
If that were not an option I would wait for nightfall, keep all lights and navigation, space blankets, sun umbrella and the jerry can of water, abandon everything else and try to hoof it. I would consider success unlikely. Given the supplies they had I would consider survival impossible.