4.2L, 33" tires and 3.07's, pulling 2000-2500 lbs up a mountain?
I would say - not going to happen. Your gearing isn't set up for towing power, for the tires you have.
I have 31" tires and 3.55 gears, AX-15. When I still had the stock 4.2L (OEM carter BBD setup) I loaded it up with about 500-600 lbs or so of wood and camping gear. It drove like a dog on the freeway and barely made 55 mph once faced with any slight incline. Trying to push it caused pinging. On steeper inclines I was doing about 35-45 mph at best.
To put the gearing into perspective:
Yellow is for fuel economy
Black is for balanced economy/power
Blue is for towing/torque