I believe a lot of it must be. How does someone get filmed that is supposed to be alone unless they set up cameras to film themselves just in case something happens? Like that scene when Sue crashes her snowmobile and gets all busted up. Did they just happen to be filming or did a stunt woman do a repeat for the camera?
I have no doubt much is real and do admire those people for what they endure as I'm not sure I could even in my younger days.
I do like the show though and have watched it a long time now. I just don't take everything I see as fact as well as many other shows I watch.