Some truck have duallies, where people can walk between, but that does not change the fact that when you google "Dual tires touching" you will find pretty nice collection of pictures.
Just becouse it did not happen to you, doesn't have to mean whole World is like it.
On my vacations on Baja, I have seen hundreds of Mexicans driving all kind of cars over the really floating white sand.
Seems the technique is to keep the speed and correct gear.
Keeping speed with camper is not always the best option, but something to consider.
It is fun after-all.