I've got the same vehicle you have now, but got mine new.
Also has the OEM General Grabber HTS tires on it. My fronts are wearing faster than the rears, but only 22,000 some odd miles on the vehicle.
I find these front tires to cup badly. Tried rotation (side to side in front) and re-balancing, which has helped a little.
Rear tires are wearing really nicely.
It may be the Alcoa wheels,(factory OEM's on my King Ranch version) but the fronts on mine are real good at loosing air pressure. Try to keep them around 65, but if left on their own for any amount of time, its back down to the 52 PSI range. No leaks found, valve stems seems good, so wheels are left right now as the culprit.
Because of cupping fronts, I have also been looking for tires.
Right now I am leaning towards the Nitto Crossteks in the 245/75/17 sizes.