In places, quick ascent or descent or odd banking of the road - so there are such sections where you cannot relax unless you have experience with the road.
Carry extra water, a jug of water plus a jug of coolant for the engine, flashlights, and a couple compasses. Also, a flat piece of wood - upon which, you can place the base of the tire jack stand.
The southwest is still the old wild west, including, that you may plan for what to do in self-defense, the weather may suddenly turn cold or wet in a flash, and tires do not last as long as they would on pavement with less, loose grit and sand.
Snakes may be in the shade. Cactus needles await your ankles. Coyotes, lions, wolves, and bears show up where “experts” say they won’t, or “experts” say something eco-nut-ical to the effect, that: You can reason with and/or have time to deal with the situation.
And on warm pavement at night...
…and take a gun. A big one.