I've done this about a dozen times. Your pretty well on your way, you have the cat crate, litter box; make sure you have plenty of water for her as well. I wouldn't bother putting food in her cage because chances are she wont eat it. Just wait until the evening when you stop. Be very careful when you let her out of the cat cage when you stop at the sites. It'd be terrible if she got away. Does you cat stress when she's in the vehicle. If so, you might consider getting something from your vet to calm her down. There are also a few things at pet stores that might work. I've never used any of that cat calm-down stuff, but I hear it works. Good luck and let us know how everything turns out.