I would set the valves, not to the heavy duty specs. When you are on the highway, the engine isn't going to get too-hot. I would suspect that if you were hauling heavy loads, in the city, that it would be recommended.
Your list looks good, although I wouldn't bother to take so much extra fuel, or water, a gallon of each should be enough. BUT, you know your truck best, how the fuel gauge works, etcetera. Last summer, I drove my Pontiac up and over the rockies and back, 1700 miles. I took more oil than that, as I know it uses a bit. -The engine hasn't been rebuilt ever. It doesn't use much more oil that the shop manual figures though.
Sounds like a great time. I might through a few plug wires in the tool box, couple of spark plugs, spare fuel filter, shop manual.
Again, it sounds like lotsa fun. My trip last summer was so much fun, we camped along the way, and only met a few jerks on the road. There are always a few people you meet, that are mad as wet hens, if you are going 50, and the speed limit is 55. I'm sure you've met them already. I find, in order of frequency, they drive: BMW's, Audis, VW Jettas, Mercedes, and caddi SUV's. Oh, and some semi- trucks, at least that's what I've found.
Have fun!!!!
