I know that staying hydrated is a crucial piece towards success in any athletic or outdoor adventures. Especially in the desert.
If I know I have a long and potentially hot day in the desert, I do my best to drink fluids constantly. I like to pre-hydrate the night before and in the morning at breakfast. No sense in starting off the day with a half tank. The same idea applies to the cats. I can't easily convince Kenneth to drink another bowl of water because tomorrow will be a long day, but I can make sure that it is always available anytime he might want some. In the morning, I try to coach him to eat as much as possible and follow up his meal with as much water as he will drink.
Once we are on the trail/climb/canyon, I make sure to stop as often as possible for water breaks. I'll give him a few drops on his head and on his paws if I am worried that he might be getting a bit too hot.
I am sure some others also have cats that are a bit finicky when it comes to drinking water. At home, we have a nice fountain water bowl that even grows grass! Kenneth and Ember still prefer to drink out of the kitchen or bathroom sink if I will give them the opportunity (and I do!) On trips, I want to do all I can to encourage them to stay hydrated. I have a small flexible bowl tht I can pour water into; once the bowl fills, I just pour that water back into the bottle. This gives Kenneth his own 'fountain' to sip from in the middle of the desert.