I have drove strait through from Detroit to Sarasota Fl. 25 hours. And I once drove from Detroit to Maine without sleep. It's a bad idea to try and I will never drive more than 12 hours again. I have horror stories and nightmares about waking up doing 85-90 mph through the fuckin mountains. Or waking up from a dream and realize your driving...these things are not good. And once your deep in the mountains or a desert and you've decided to try and keep going...you may not have another chance to safely pull over...at thats when things can get scary. It's really best to just add an on a day or two if you can...and drive like 12-14 hours, then rest for 4 hours. The road will screw with your head at night...in Vermont I had been driving for 20 hours, it was 3am, and I was the only car on the road. No street lights+new blacktop+fresh white painted lines+Mountains= I almost fuckin died. The black road, dark sky, and mountains all look the same...and I kept falling asleep. And no rest stops in that whole state I guess...I was fucked...so be carfull.
Good luck
Peace