Another interesting side note about this most forbidden place.  I am a forester and surveyor as a result I spend an inordinate amount of time in unpleasant forests as well as pleasant.  The area on the river left of the gorge (and for all I know river right too) is of the highest concentration of yellowjacket ground nests I have ever seen.  I personally took 12 hits off about 7 separate nests while scouting one balmy August day.  Furthermore, the concentration of devils club is among the highest as well.  To complicate matters even further the edge of the canyon in many spots is hidden with loamy vegetation.  In some spots the vegetation is actually attempting to close the lid and grow across the top.  Word to the wise is to not even approach the "edge" without being roped in or you may find that you are hovering over the abyss with only a rotten branch held together by moss as a perch.

Dude I can see it now, scouting a deep canyon run wearing a bee suit, harness, roped up and whacking through the devils club only to miss the run because you walked over it without knowing... I am oddly interested too now, not that I will likely act on the interest. 

Somebody has got to go in there.  That somebody will not be me.  Unless the fearless sombody who goes first reports "great whitewater in a sureal fantasy canyon".  I wonder if any canyoneers have ventured in there?