<< I just got back from visiting SoCal, and it's about a six and half hour trip one way. I've made it twice now, down and back, and I can do it w/o stopping. This time I stopped for gas but I didn't the last time down, just went straight through. How long can you drive without a break? >>
That's just wrong. Just plain wrong. 6 1/2 hours straight? I think I'd rather shoot myself than take any trip straight. I can't stand car trips. Period. When I was younger and my family used to go on vacation we would drive everywhere. The longest trip we ever took was 18 hours and it nearly drove me insane.
To answer your question, I think the longest I could drive straight would probably be a few hours. The only way I could go any longer would probably be if I had some good company or some great music to listen to, other than that I have to get out and take a break from the open road.