ifish4wildtrout--To quote him in his report, "I was whupped." He had tremendous problems with really thick briers, witch hobble, and rhododendron hells, not to mention making a mistake in follow some surveyor tape along an opening which looked promising. His conclusion, after backtracking to McGee Springs and soaking his feet (briefly) in its icy water, was that this was a trip to be made in late winter or very early spring.
He tought about altering his plan and taking the Right Fork of Three Forks down from McGee Springs to Three Forks, but didn't do it for precisely the reason I posted earlier--it would have been a deviation from his mapped plan.
P. S. He sent me a photo of his scratched legs. They were something to behold!