Palomino Maverick M-800 on 2018 GMC 3500 STD BOX 4x4

Can’t comment on the camper specifically but it’s a good fit for your 250.
Unless you have a camper package 250, that gen of 250 is soft in the rear. I’ve had a couple of them.
Bags or springs will be needed for sure. And a large rear sway bar will be preferable. If you have an OE sway bar try it first. If you have none and have the budget just get a big sway bar. You’ll want it. No questions.
Sounds like fun.