I have a Ram 1500 with a mounted Phoenix Pop-up camper. Fully loaded the rig is about 500 lbs overweight, pretty much the same situation as yours. I immediately changed out the tires to “E” rating.. based on previous experience. Coming up on 35000 miles; never a tire problem. I also installed Timbren DRTT1500 SES Rubber springs and have been really happy with them. These replace the jounce bumpers and are permanent.. Air Bags are useful if you take the camper on and off, but ours stays on all the time. Truck handles just fine.
. . Kurt