If you rebuild your original brakes, they will perform perfectly well for all types of driving that you're likely to do in that truck.
Drum brakes are not inferior to discs, contrary to popular belief. The primary benefit of discs is their resistance to overheating during repeated high speed brake application. Unless you plan on running a gymkhana every weekend or riding them down Pike's Peak, you'll find that the properly rebuilt and adjusted Huck brakes work very well.
Tractor trailers and dump trucks all use drums, not discs.
