Actually there is a TSB out to address just that issue. The F250 will squat under light loads, even though it has a tow package and truck camper suspension package. It has something to do with the size of the blocks where the leaf springs mount to the axle. The F250 has 2" blocks, while the F350 has 4" blocks.
Because of the expense involved in installing the 4" blocks, I'm not entirely sure I'm going to mess with it. It's entirely cosmetic, and the front doesn't come up at all.
The 650 pound tongue weight of that camper is well within the capacity of the truck.
Here you can see my Summerland Mini with it's 250 pound tongue weight does the same thing.