I can't drive at night at all. Even if I wasn't tired when I got in the car, I'll be hallucinating after an hour or so for some reason. 
I like to drive in the wee hours of the morning (just before sunrise) and let the day keep me going. As it was recommended above, you might want to nap from time to time throughout the trip. If you feel like you might fall asleep--even if it's the slightest indication--find a rest stop, set an alarm on your phone for at least 45 minutes, and pass the hell out.
Stay your ass away from caffeine for as long as possible. I don't recommend energy drinks because they'll knock you out after an uncomfortable, jittery rush. If you drink too many, you'll also have to poo and it won't be pleasant. Try caffeine-free 5 Hour Energy in Berry flavor. They don't give me any sort of rush, but they seem to keep me from wearing out--it might keep you more alert. Use caffeine as a last resort and give it about 30 minutes to kick in (a good time for a nap!).
The longest road trip I've been able to do was about 30 hours straight (NY to Williamsport, PA; to York, PA to switch cars; to Valdosta, Georgia). I wanted to kill myself.
Seriously, don't fool yourself with the A/C and loud music. It probably does help for a little while, but hey, you're driving a car and that alone isn't enough to keep some from falling asleep! E36 M3, I sleep with my A/C on in my room for the noise and the cool air.
