31k sounds good, but I would never give up payload unless I was going to downsize the camper. All the 1500 Rams I looked at, both diesel and gas, had payloads that were barely more than the Frontier I was replacing.
Unless you get a camper that has a really large cargo capacity, I believe that just putting any additional stuff in the camper to keep within payload specs is going to be problematic. I don’t know anyone who has lightened the load in either truck or camper as time goes on. Sorta like people, the weight just magically grows ;-)