For the sake of discussion only, the specs on a 2002 GMC 2500HD SL, 4x4, Ext cab, long bed most likely are:
Truck
GVWR 9200
Payload 3807
Tow 10300
Curb 5393
Trailer:
GTW 7000 (a guess)
Curb 3272
Assuming:
3272 = Trailer
2000 = Trailer load
5393 = Truck
3507 = Truck load
GTW = 5272
GVWR = 8900
For load I used:
400 = 2 pax & cab stuff @ 200 ea
2500 = Camper (1700 dry + 800 water, propane, food, & stuff)
527 = Tongue weight (10% of trailer GTW)
80 = Hitch & such
Doing the math … it seems like you've around 300# of load & a thousand plus of tow available.
No idea about axel weights or how such a set up would drive over the river & through dale … & I could be totally wrong about all this ...