So, it looks like the Z82 package for this model is just the hitch and the 7-pin connection. What I need (and regrettably not able to locate on the RPO's) is the K5L package.
This is the Trailering Package, heavy-duty, includes (KNP) auxiliary external transmission oil cooler, (KC4) external engine oil cooler, power steering cooler, increased capacity radiator and cooling fans and (NQH) transfer case, active, 2-speed
1 - Includes (GU6) 3.42 ratio rear axle. Not available on 3/4 ton models.
2 - Not available on 3/4 ton models. Included with (PDA) Texas Edition and with (PEB) Regional Value Packages. Includes (GU6) 3.42 ratio rear axle.
Sad face here. So, i've asked the dealer for an estimate (minus the gearing swap basis all of your suggestions) for the coolers, radiator and fans. 80% of the time, i don't think i'd care about the radiator as we don't plan on going anywhere too hot. But, my main concern on the department is to engine temp at altitude. We do quite a bit of camping back though about 60 miles of mountainous terrain starting at about 1500' and maxing at about 7000'. Last place I want to have a problem since i'm already starting with an arm tied behind my back in this fight.....
Further thoughts or suggestions?