From time to time I have slept in my Xterra or van. I usually do truck stops or a rest area. Sometimes it has been to save money, and other times just safety, just too tired to keep driving. Bring a mask unless you have something to block the lights. I asked a truck stop if it was ok I slept for a few hours, they just looked at me like an idiot, because of course it is ok. I also slept just off the cap rock once cause I couldn't make it to Lubbock since I was so tired. It was nice waking up to the terrain that's just where the caprock ends. If you are continuing chasing, while not cheap, I do recommend a truck stop shower. Most are very well kept up, and it's amazing how much a shower refreshes you for the day. Have fun, good luck.