Some notes about the unpaved road:
1. I took my 2WD sedan over it. Although it is possible to go there in a sedan, I regretted my decision to take sedan over that road. Last 15 odd miles took us little more than an hr to drive, whereas couple of SUVs were just tearing away at 50mph on same road.
Well, they were wearing out their steering linkages and suspension parts, and you weren't. Anybody can drive fast over the washboard roads, but it isn't good for the car. I've driven 4WD high clearance vehicles over the road, and figure it takes about an hour for the last 20 miles.
I have a theory that if everyone with 4wd would use the 4wd mode, it would help prevent the washboard effect. I think it is minor slippage and a slight bounce by hundreds of 2wd cars going over the road that creates the washboard.
