Planning a 440+6 tow vehicle, need a plan

if has to wonder what the frames were on the 60's 3/4 t. D200???? thinking years back, chevy had their " camper special" seems it was a 3/4 t.
I admit I bought a new '76 1 t. chevy crew cab 454 , that is what we pulled with. I had a 3/4 t. 75 chevy single cab 454 right before that. the dual wheel 1 t. truck was much more stable, bigger brakes, just a much better rig to pull a big steel 4 horse gooseneck.
best pullin truc k I built was a chevy C65 ( 2 2/2 t?) 427, 5 speed, 2 speed axle. added a sleeper box and built a custom bed, circa 1983. no days horse people consider that med duty!! ha
I know there are clubs where people buy these old campers, rebuild them, pull them with vintage vehicles, and meet at " what ever they call it" camping things. you might be able to find such here on the net. would be interesting to get some of their experiences with all this!!!