I would invest in a sway bar (preferably a HD aftermarket one) before I would buy air bags. I am not anti-air bag, but in my opinion (and others, apparently), air bags are more useful for load leveling than sway control and adding them can worsten sway problems, depending on pressure used. Too much pressure and you raise the load off of the factory springs. This negatively impacts sway control. I ended up going with a custom 5 leaf overload pack. With my sway bar, ranchos maxed, and custom springs, she handles very well with my 2714 lb camper. Nonetheless, nothing beats the stability of a dually! Oh, well, next truck.
Dave
P. S. I am firmly in the "mount the camper to the frame" camp!
My 2 cents.