I don't have any issue with the placement of the cat. It looks like the slope flattens out down where the cougar is, and it also looks like the cougar is standing in a trail through the underbrush. The focal plane on the cougar's feet is also similar to that of the surrounding brush. Like I said, if it's a fake, I think somebody went to a lot of trouble to lug a full body mount out into the woods with them, but people have gone to much more trouble than that for a hoax (Balloon Boy comes to mind).
I certainly don't think it's impossible for a cougar to come this close to someone, as I've known people that it has happened to.