air bags to increase load/ride height?

[wildbio]

I am installing a slide-in camper in the bed of my 2000 Dakota w/ 4.7 liter V8, 4x4, 31x10.5 tires, 5 speed, extended cab. The weight will be approx. 1000 pounds. There are no suspension mods. I was wondering what the best options are for maintaining ride height when loaded. I do not have ABS brakes but am told the non-ABS rear brake has load-proportioning valves that would be affected if I install air-bags (firestone or airlift) or helper springs. How do I know for sure if I have the valves and what is the recommended load assist if I do? Also there are factory over-load springs. Thanx!