Not a CDL here, but 40+ years of off-roading (grew up in the southwest), camping and RVing. My brother-in-law has a 4x4 diesel to pull his fiver - and has still had to use the winch on the truck to get off BLM land after a surprise snow (he and his son use the rig for hunting a lot). Living in the southeast, now, I chose 2WD because of the reasons listed above - higher payload, better mileage, lower maintenance cost, etc. Only once have I wished I had 4WD, and that was when the truck was on a grassy, uphill slope while trying to rock the trailer into a spot at a rented cabin in the Smoky Mountains. I think that situation would have been better with a fiver with more weight over the rear axle rather than my travel trailer (hope to move up to a fiver soon...).