there are some rest stops, especially the bigger ones, where you can grab a shower- or even a place to wash your face.. sometimes the cold water just perks you yp...
there's this contraption that you can get - that goes behind your ear - that zings you when youstart to drift off to sleep.. you might want to consider one...
Every few hours, stop the car, and do afew laps around the car, stretch your legs, go for a walk, pee if ya gotta.. but keep yourself active...\
It's a long drive,. make sure you have a fully charged up cell phone with you, AAA numbers if you are a member, i'd even get a membership just in case,. make sure your spare is in good working order and you have a jack and know how to use it. Have some extra water in the car for the radiator just in case... (it'll be hot, you never know) and don't pick up any hitchhikers- even if she's hot looking, those are usually the homicidal ones