"I have never dealt with such high temps and relentless sun (I'm from Canada)."
Planning is critical. You HAVE to know where the reliable sources of water are located.
Also you have to drink frequently, just small amounts of water to stay hydrated. It is the most efficeint method. Craig just did two days in what is arguably the hottest desert in North America. Craig is an accomplished desert hiker, and would drink water twice as frequently as me. Since I live here, my body is more acclimated.
If you get to the point where you are very thirsty, you are not drinking often enough.
BTW, did you see any rattle snakes?