I'm sorry but this road sucks the big one. I've driven several backroads in Arizona class 5 and below. I have a 2003 Tundra 4x4 and I only made it half way up the second "step". You could say I was a little bitter at the fact that we got up early and drove from Prescott Valley only to be stopped by this obstacle.
I could have made it, but wasn't prepared for this kind of offroading, and consequent damage to my truck thats not paid for yet.
I'm thinking of going this Sunday with about eight eighty pound bags of quikcrete concrete and have at it. Thinking about stacking some, splitting,pour water on and leave to harden and drive over.