From the time when I was doing equipment hauling, I remember that none of the pickup till 550/5500 series are design for hauling heavy weight in the bed.
Take a look where the rear axle is placed? On trucks less than above the axle is placed at about 50 percent of bed length. That makes it good for 5th wheel, or grocery getter.
You hook up heavier trailer and you need WD bars to compensate for "grocery getter design" with huge rear overhang. To top it, the manufacturers have no idea how truck camper affects the trucks.
For my new dually camper package was offering ONLY stiffer FRONT stabilization bar.
My camper takes the weight off front axle.:S