If the camper weights 5600lb and the rear went from 3500 to 9250 lb, the remaining load had to come from front axle.
All those measurements come with +- 100lb error margin as one time I had DW + dogs, the other time some tools in the cabin.
I don't mind overloading the axle as long as the tire have some room to spare. My 4 rear tires give me 11,640 lb load capacity, so I am good.
Today I put another 250 miles to finish 300 miles tomorrow.
Averaging 12 mpg with CC at 65mph.
The truck enter 5th hundred on odometer. So far everything looks very good.
I know not much can be done to side wind sensitivity, but on freeway joints, occasionally the truck porpoise more than my liking.
I remember such issue with F450 and air bags cure it quite nicely, but bags for 2017 models are priced out of proportion and the problem is too small to justify the expense.