Once, a few years ago, I went to gencon and was driving back to jersey. I almost wrecked myself a half dozen times dozing off while on the highway. It was the middle of august and a scorcher. I would pull over at a rest stop to try to sleep but within 15 minutes the inside of the car was like an easy bake oven mounted with a 1000 watt bulb. I would immediately wake up sweating like I was in a sauna and would get back on the road with the AC turned up. Once the car cooled and before I had gone so much as 10 miles, I would start to doze off again. I repeated that cycle a bunch of times and it was not a pleasant trip.
Oh well. Worrying about sleep deprivation is probably stupid anyway. It's like worrying about a papercut when an asteroid is about to cave in your skull. If the whole pain situation goes over well, I can deal with the sleep thing. If the pain situation isn't good, sleep is going to be a minor concern anyway.