I halfway feel badly for Mr Supertramp, but he was just another misguided young liberal child. When I went to produce a documentary on Denali in 2002, I discovered that the bus was easily within hiking distance of the main tourist road up to the visitors’ center. Of course, LOTS of Grizzlies but he was no where near being “remote”.
Addendum: I guess I don’t know which side that river was on, so I amend my “easy hike” comment.
From what I read of it, he ate some plant which was bad and got very sick (vomiting or diarrhea, I can’t recall); to the point he was unable to walk.