I travelled three hours back to my Father's house for a few years with Tank. I used a twin size sheet that I whip stitched on three sides. I usually travelled at night and had the heat up high. I put a coat over him to keep it dark and put pillows on the floor in case he fell off the seat. He would be twitchy for a few minutes and then pass out. Being anal, I also put a note on the dashboard advising that I was carrying a reptile, in case of emergency.