All of it is total bullshit!!
Buddy of mine knows several of the behind the scenes support crew that was hired up there and has wheeled with them a number of times in several of the the places shown. The support crew was made up of a bunch of the local wheelers and were hired for logistical support, mechanical repairs, offroad expertise and local knowledge of the area, what I'd consider the real Alaska wheelers.
Anyway, as the story goes the level of BS got pretty deep, at one point the producers were trying to do things that were so stupid & dangerous that the local support crew walked off the job until the producers were forced to back down. Furthermore, while the show depicts the teams making their way on a single long trek through the Alaska bush the truth is that it's really series of day rides all stitched together with a few contrived camping scenes thrown in for effect. Apparently the "warriors" would be shuttled to the nearest hotel for the night while the local logistics crew would load up the rigs on trailers and haul them up the trail 150-200 miles, offload them, fix the broken junk and then the "warriors" would be shuttled back the next day for yet another day ride.