Climbing steep grades...

If you want to tow, add separate coolers. My dealership had the CHP account with those older Mopars with the 440's. They had Trans coolers, Engine oil coolers, Power steering coolers and a Max cooling package. These would never overheat going up a grade at 120mph. In your case make sure to switch off the A/C when going uphill. You don't need the additional heat from the A/C condenser. Add a trans cooler and disconnect if part of the engine radiator is used for trans cooling. Worst case, I helped a guy with a overheat issue. The radiator was too small to handle the heat, so we used an old windshield washer tank and pump to direct water on the front of the radiator when getting hot, old school but it works.