The main thing to remember is DO NOT RIDE THE BRAKES! If you can use your gears/engine to keep your speed in the safe range, that's ideal. It doesn't take much to overheat the brakes descending these mountains and have NOTHING.
I've been driving mountains for 50 years. I think nothing of it. But about a decade ago I found myself a brand-new wife. Who happens to be scared stiff of mountain roads. So as we're inching down a jeep trail in my old F250 4x4 back then, with a ton+ of TC camper in the bed, new wife is trying to mash her footsies through the passenger side floorboard. So I touched the brakes. And touched them some more. And some more. And about the next time I touched them, the brake pedal went to the floorboard and we were without brakes.
Luckily, we were very near the bottom of the canyon at that point, and I was able to find a little rise in the steep descent and pulled off the trail pointed uphill. I think it was the following year that an older couple in a motorhome was coming down the same mountain a few miles away on the highway (Hwy 16 near Buffalo, WY) and lost their brakes. They ended up inside a building in downtown Buffalo. He was killed.
These mountain roads are easy to drive when you stay on most of the major highways. But be mindful of the brakes overheating. They really give you no warning. Use the gears all you can, and when you need more, use the brakes firmly to slow rapidly, then get off of them and let them cool.