How to increase payload?

I have a 2015 Coachmen 324 TSRK, it has a dismal 1284 lbs of payload. It has 5200 lb axles. It was one of only two models produced by Coachmen that year that 7000 lb axles were not an available option. I know I cannot change the rating on the yellow payload sticker. But what would be the harm in changing the axles, springs, brakes with 7000 lb axles, springs and brakes? Would I be safely increasing my payload? What about just changing the bearings to 6000 lb bearings? It it my understanding the only difference between the 5200 and 6000 lb axles is the outer bearing? Thanks in advance.