Joel...keep in mind that 4100+ lb payload is a GVWR based payload and when placed in the bed over the trucks 7000 rawr will over load it.
A gvwr based payload works fine if say a over head rack that sits in the bed and the overhead part sits in the trucks frame at the front. That way the 4100+ lb payload can be spread over the trucks front and rear axle unlike a bumper pull or a 5th wheel/GN trailer thats all on the trucks rear axle.
You have the truck so drop by a set of scales and weigh the trucks front and rear axle separately. Many trucks that size rear axle weigh in the 3400 lb range as it comes from the factory. That leaves your 7000 rawr with approx 3600 lb max in the bed payload. Scaled weights tells the story.
By the way....that 4100 payload or the trucks gvwr has no legal status if dot was to ever weigh you pulling or carrying a rv or... a load of rr ties from Lowes .... a bed load of 1 1/2" crusher run gravel or any not for hire work.
Stay under axle/tire load rating or a registered weight of some kind per your state and you won't have any legal issues.