TCcampsrnoob. Stop, step away from the keyboard for a minute and re read everything.
First you need to know a bit more about tires and wheels. Especially if goin to 19.5s. You don’t want steer tires in the rear.
Also step back and re read what you’ve posted. You’re off on a tanget of 19.5s and 4 pages ago you said you weren’t buying a camper that needed them.
AND, if you’re worried about all this, how are you not worried about exceeding your gvw and other “ratings?”
And yes a 4wd truck is rear wheel drive when in 2wd mode......