I'm a student (Vineyard Operations) and live in Napa, California. Last year's harvest I averaged a 1000 miles offroad per month in vineyards all over Napa and Sonoma counties. Never got stuck and I was in some very steep mountain vineyards. By the way the truck of choice out here for vineyard operations is Ford, followed by Dodge and last place of course is Chevy.
I drive a White 96' F-150 2dr XLT 4WD extended cab. 351(220hp)Windsor. Flowmaster, K&N, BF Goodrich All Terrain.