When my back road rides were longer they were plotted according to what water points were available. I do not tolerate thirst well. Dehydration and exhaustion are sneaky sneaky. They will come up on you and put ya down. Even the most experienced have had issues now and then.
Ridding through hot dry terrain is a survival skill...
__________________
No matter where you're at... There you are... Δf:=f(1/2)-f(-1/2)