My experience with 19.5's on my 2002 Super Duty was a rougher ride because of the stiff side walls. That truck was stiff already, so almost unbearable even with Rancho 9k's. I also had to put it in 4X4 backing up my sloped driveway when raining because lack of traction. The first 1000 miles were down right dangerous because of "tracking" issues, got better after a while, still a kinda bad when I sold them for a $700 loss and about 3,00 miles or so.
I know some people on here dig 'em, I hated 'em and sold them. The piece of mind with 7500 on my rear axle WAS nice, when not tracking into the next lane. I went with BFG TKO 2's after selling them, they sucked also. They caused trailer sway on a perfectly setup TT, heard of others with similar results with TKO 2's. I FINALLY found a good setup with Michelins and a DRW.
My setup was Vision 81's with Roadmaster RM253's.
https://simpletire.com/cooper-245-70r19.5-71845-tiresGood luck with your new setup, really like that camper you're picking up, A LOT. Hope 19.5's work out better than they did for me.