Whoa, no jokes about the wife making good ballast! haha
Made that mistake once when we were surfing behind the boat! Never again, she can sit where she wants!
Yes obviously cant move the camper forward. You can try to get as much heavy stuff forward in the camper, of course putting stuff in the overhead will stress it out and make you more top heavy.
Do you carry a generator or anything heavy on a rear hitch rack?
Could put a front hitch on and load up heavy items off the front bumper.
Is the truck a long bed? How long is the camper?
I know my setup would do the same thing on a IFS truck.
Does your DMax already have a leveling kit,(leveling keys)? Those throw off the camber if not re-aligned.
You may actually have some positive camber already before loading up the back of the truck. Might not all be due to the camper weight.