You could use an over-sized WDH to move some weight of your rear axle to the trailer and front axles. At certain point, you will get poor trailer handling and may also over stress the trailer tongue if you are trying to compensate for an overloaded rear axle.
Perhaps you could provide us with some detail of the truck and camper and some actual weights on your three or four axles so we can help you?
I was able to load my truck camper and tow a 20' enclosed with 18" OEM wheels while staying under tire and rim capacity by distributing 1/3rd of my tongue weight to the front axle and 1/3rd back to the trailer, but I had to be careful how I loaded the camper and trailer to minimize rear axle weight. Never did I crank my WDH up so high to actually unload camper weight off the rear axle. I ended up going to 19.5" wheels that had more capacity and was able to stay under axle ratings without having to play load master on each trip we took to stay safe.