I'm sticking to my guns on this...a 3 point turn was not possible. I'm starting to think I may need to go back and get pictures of this.
As far as sleeping goes, he may have gone in there thinking he could sleep behind it and then realized he couldn't too late? But my theory I think makes the most sense with what we have (as far as how the accident happened).
Going to sleep doesn't really make sense because by then it was 4:00am approx. His accident happened there, so he was there likely very close to that time, so by then he already had been there for 2 hours and likely already slept.
The accident occurred after he went to sleep based on the time line and what I could see. He probably got off the free way on Lake Hughes Rd. He continued on that road for awhile, when he finally found the turn out for either the flying lessons or the church and went to sleep there. When he reversed out either of those turn outs he likely went the wrong direction. He realized he went in the wrong direction, saw the driveway and tries to accelerate to get up the ramp (it's steep), and by the time he realizes that's not an area you can use to uturn, it's too late and he's going down the hill.
I don't think I'd consider turning on my 4x4 and going in to reverse when going down a mountain, I wouldn't even know it was possible, I'd be holding on for dear life.