265/65R17 is stock. BFG makes the AT's in that size IIRC
If you want slightly larger but no rubbing issues....BFG also makes that tire in a 265/70R17. Fits no prob. They make it in 2 load ranges C & E....go for a C for better ride quality or E for a tougher sidewall and more load capacity.
headfirstdesign - I put BFG AT's on in Jan08. 265/70R17 LT's. Got the LT's for a tougher sidewall w/ higher load rating. Great tires that fill the wheelwell nicely, with no rubs stop-to-stop. Only complaint is cold weather ride....the thicker sidewall makes for a stiffer ride when cold. BTW - this is on an '05 D-cab 4x4.
Go with the load range C. E is severe overkill for this small truck. If you inflate to their maximum pressure of 80psi (I doubt the factory wheels are even rated for it), you will likely experience uneven treadwear. If you run then lower than that, the sidewalls may experience heating and degradation. The ride quality will be harsh, unless you are into that sort of thing.