The amount of weight transferred back to the front reducing the rear end squat by an inch or two is minimal. You are not changing the relationship of the camper's COG to the rear axle of the truck by much, a fraction of an inch at most.
Since you don't have WD bars to pry up on the truck's frame using the front axle as a fulcrum, the only effective way to transfer weight forward is to... transfer weight forward. As in, physically put heavy things towards the front of the camper.
If that is not feasible all you can do is live with it as-is.
