Lots of opinions here but I'd do away with the airbags to start...sooner or later they'll fail and there are so many more modern choices available. First, I'd take it to someone in your area that does custom spring work!! Take the truck to them with the camper loaded so they can see what you've got and how it's affecting your stock setup. They'll probably recommend a three stage leaf spring upgrade that will properly carry the weight with steel!!
In addition to this I would look at new shocks...Bliestein makes a great shock that's designed for your truck not a one size fits all like others.
Once you've done this then based on ride etc you can add the torklift stable loads and or timbrens!! Of course consider 19.5" wheels and G or H rated commercial tires from a place like Rickerson's.
A quality suspension will give you maintenance / trouble free years of service and the confidence to maximize and enjoy your camper to the fullest.
Best of Luck
