You could always just kick the can down the road and get a
new set of LT235/75r15(C) on the stock wheels.
If you're all or mostly on pavement you likely won't have the tire damage. We didn't have any trouble with the tires on our Suburban the first couple years until we moved out here ten miles off the highway on gravel/dirt road. Then we started getting flats all the time it seemed and many of them not repairable.
Our Suburban apparently ran on P235/75r15(B) tires for 140K miles before we got it. I swapped them out for LT(C)'s pretty soon and I think I still have the factory spare sitting out there in the shed
Of course our Suburban has the 700r4 with overdrive so highway speed rpms aren't so much of an issue. But 70++ does kill the mileage down to 12 or 13, but at 65 it gets (or used to, anyway) 15-16. We drive it so little these days that even when I take it to town on the highway I just leave it in Drive. The extra rpms are probably good for the engine once in a while.