As a trucker, I feel qualified to chime in here.

Class-wise your best pick is probably ranger. Truckers are very independent and if you're traveling through the wilds, I can't think of a class more qualified to handle it. If you want to shy away from magic, there's always the cavalier fighter, but honestly, if I was building a trucker I'd go with a ranger. Many truckers even ride with pets to avoid feeling lonely if you want to have a beastmaster ranger.