During my next story, the PCs will be spending some time in a desert, but I'm confused about somethings. What are the rules about desert travel? Do they have to make a check every hour? Are there rules somewhere for desert mounts? What can they buy to help with the heat. The SRD has cold weather clothes, but not hot.
Besides just monsters, I'd like to possibly have friendly/neutral things to find. An oasis for example. What else might there be?
Any advice would be appreciated.
Bueller?
I'd have to search for it, but the Core Rulebook does have rules dealing with Fort Saves for heat exhaustion.
You might want to look at the Legacy of Fire AP for ideas, particularly book 3, The Jackal's Price. It include a trip across the desert including a battle with a sand worm. It also includes the set piece adventure, "Hell of Eternal Thirst", that takes place at an oasis in the desert.
Anything else related to the region of Katapesh in the Golarion campaign setting may be helpful as well for information.