Taking a Cat on a 15-hour trip: break it up by 1 night or 2?

why would u be driving in the sun? arnt u in a car? i think for less stress you should do 1 night. it is easiest to keep him destressed. keep him in a carrier with enough room for him to turn around and go potty in if need be. and keep water in the crate. keep the air on him and maybe put him on the floor so he is in the shade or something. i think he should be fine