The single most important tip I can give you is: make sure whatever jack/lug wrench you use to change tires is easily accessible after you're packed up!
I know this sounds like an obvious one, but when I got a flat in the middle of Glenwood Canyon on I70 several years ago, I had to unload my whole, blasted, chock-full XJ to get at the tools under the rear seat (which was folded down). My spare was on the roof, but didn't even think about the jack when I packed. My Hi-lift was accessible, but not the bumper attachment either! That was a real thrilling tire change - I70 was still under construction through the canyon - 2 lanes - no shoulders - semi's rolling by 3 inches away . . . .!!!
Other than the other obvious things - u-joints are nice, but, if you can afford the luxury, u-joints already on spare axle shafts is even better. A length of radiator hose, and some clamps. Critical fluids (oil, coolant, gear oil, even some good old water). Roll of shop towels, mechanic's gloves, old blanket - you'd be surprised how simple things like that make a roadside repair not so grueling. While a full tool box is nice to have when you get to where you're going, I take the more common sizes of wrenches, sockets, screw drivers, duct tape, wire ties, etc. and put them in a separate bag for easy retrieval/use on the highway.
And, finally, a good portable light (battery or plug in) that can be positioned w/o having to hold it in your hand.
Enjoy your ride, I'll be headed to Utah again in a couple of weeks and if I do something else stupid

, I'll let CHW know so he can post a warning!
Mike in NJ