Need help with rim choices

[GMC69]

The tires are 3 years old. Store the truck in a heated garage and if I'm not driving it, it's parked in the garage in the summer.

With the little bit of driving I do, I figured I could get away with a softer compound and still get years of use out of it.

Just looking for some brand/model of tire that might work. I'm guessing 18" rims will give me the wider tread width with a more square sidewall.

It doesn't help that my 3 year old likes it when I push the truck a bit with quicker take off or going into passing gear on the highway even if we are the only ones on the road. Won't be long and he will want the keys to the truck.