It looks like your front end is unloaded with the camper on the truck. Here is a pic of my truck when I picked up my camper. This is a stock suspension with the camper package and it sits level. It is a 5.9 gas auto so I don't have as much weight up front as you. The camper weight is 2580lbs. With the camper on it just touches my overload springs. Truck and camper (dry) weigh 8380lbs. No people or gear full tank of gas.
I read someplace if you have rear drum brakes that you can get rear wheel brake cylinders for a 3500 and they are bigger and improve braking.
