The tires should hold for a while. I ran that size in a goodyear wrangler hp tire on a 1500 chevy, and dw's tahoe. I think those tires (goodyear wrangler hp) are junk personaly. I broke bands in 7 out of 8 tires I had, with over half tread left.
Yes you will need bags most likely. Most of the ram 1500s ive seen have had a cargo weight (passengers and cargo included) of around 1150-1350 lb. So with your hitch, tongue weight and a couple people you will be at the max.
Ps. They ride smooth, but not rated to handle much more payload than a car
Good luck on your decision!!
MillerTime- Future Sabre Handler!!