Yep, definitely the driver. I saw a Lincoln Towncar coming out of Pine Canyon last year. I'm sure it was a smooth ride, but it wasn't exactly high clearance :D
um, let's not forget the importance of the vehicle. It's not just one or the other....a good driver and a good high clearance vehicle is the main force here....but the weather changes as much as Micheal Jackson changes his nose.......a lincoln towncar on any of the backroads is not a good idea. (except for maybe Grapevine or the front half of Paint Gap)