Well... I guess it's just that he's done such a bad job of faking the engine out parts of the video, it'd be weird if there weren't very obvious errors he'd made in the other parts if he was faking much of that as well. I realize he's done a lot of chopping and changing with the sequence and timing of parts of it, but if you look on Google earth you can find the bit where he follows the canyon down and gets stuck at the cliff. He may well be exaggerating the time taken in the video, but at the same time, I suspect hiking down from the crash site carrying your parachute is probably harder than it looks.
It wouldn't surprise me if the 'waaah I've got no water' thing wasn't true, but then at the same time he doesn't seem like the sharpest tack in the box, so I feel like he might also have decided that he'd be out of there in two hours and wouldn't need it.