John,
I installed the Hellwig part number 7658. It's an easy bolt-on job. For more information, here's the Hellwig application chart:
http://www.hellwigproducts.com/antiswaybars/domestic4x4_dodge.html
The best improvements were the Rancho shocks (set on 9 on the rear and 7 on the front) and the anti-sway bar. The anti-sway bar helps with cornering when driving the truck solo. Also, the bump stops helped which transfer more of the weight to the much stiffer overload springs.
I could probably get by without the air bags, but I used them in the past to raise the rear of the truck to level. I don't use over 30-40 PSI air in them and could easily get by running the minimum 10 PSI in them. The truck/camper combination handles much better when the truck's spring pack is carrying the load vs. the air bags.
My truck is 2-wheel drive, I don't have any modifications to the front other than the Ranchos. I don't think there is anything you'll need to do to the front suspension other than the shocks.
I run 80 PSI in all my tires. Not only do the tires run cooler, the sidewall "squirm" in radial tires is reduced at this pressure which relates to less sway when hauling heavy high center of gravity loads.
My truck isn't a "daily driver" and sets most of the time with the Lance on it. 95% of the miles on the truck come from hauling the camper and we never unload the camper once we leave home.
As far as tiedowns, I've used both the Happijac and Torklifts. Both work well... your choice. I use the Happijacs currently because at the time I rigged out my truck, the Torklift tiedown chains interfered with the fuel door. I thought it too big of an hassle to loosen the tiedown to refuel the truck. Be sure and use a rubber bed mat under your camper to prevent from moving on the slick truck bed.
Bill