I have been following this thread, and feel the need to put in my $02.
Adding airbags to a 1/2 ton truck does not increase the payload, or the GAWR......it is still a 1/2 ton truck. A 5th wheel trailer is going to exceed the GVWR, and probably rear GAWR.
The listed payload capacity is misleading. On my truck the title lists 5236 lb. empty weight, with a GVWR of 7200 lbs., giving me a payload of 1964 lbs......don't believe it.
I have weighed my F150 with me in it, 3/4 tank of gas, less than 100 lbs. of personal gear, and TracRac rails only, and I am right at 6000 lbs. That gives me an actual payload of 1200 lbs.....below the listed
dry weight of the 5th wheeler in question........and that is empty weight. What happens when you add a 100 lb. hitch, the wife, kids, and other camping supplies, plus the added weight of the hitch when the 5th wheel is loaded for camping. The total is going to be well over the GVWR of the F150.
IMHO, most 5th wheels should be towed by a truck that has a full floating rear axle, ie a 3/4 or 1 ton truck. To put that kinda weight on a semi-floating axle found on 1/2 ton trucks is going to cause premature axle failure.
Put this question out there on RV.net and see what kind of answers are given......I betcha those will not be near as mild as the 1s given here.