Hiya,
Just wanted to pipe in..
I've driven quite a bit in the USA and Canada, mainly north east area. I haven't got as much experience as others here but I would like to add the following
1. Have as comfortable a car as possible. I hired a pontiac sunbird out of Queens NYC, drove to Midtown Manhattan, had a few drinks with cousins and left at 6pm to drive to Cincinnati. Although the car was newish, after a while it did become a little uncomfortable. To help, I used my jacket as a cushion, adjusted the seat every so often.
2. I 2nd having appropriate music to help pass time and fit the mood! - As I did the NYC>Cincy stint mostly in the dark, I had some of my fave tracks pumping away loud and keeping me awake/alert (mainly Club/Dance music) - be careful though, some music can make you drive fast! (my NYC>Cincy>Detroit>Toronto>Detroit>NYC trip over 10 days netted me 4 police stops and 3 of them got me tickets! as well as about 4-5 police tails where I knew they were radaring me but I wasn't stopped)
3. Get yourself a GPS unit to help you, if your directional skills are up to par, and you dont need a GPS unit, have your route pre planned and printed out and easily available!
4. Try not to go overboard with energy drinks and snacks etc - when I got to Cincy at 330am that evening, if you'd have seen my eyes you would've probably taken me to hospital! - I was proper wired!
5. Make sure someone knows your route. I was utterly disapointed at how crap mobile phone signal/coverage is there, and especially on LONGGG stretches of those wretched crappy 2 lane 'highways' - I thought if I break down here, no one will be along in hours and I wouldn't be able to let anyone know.
Some of this you may already be used to or know about !
Good luck with the drive!
DtM! West London & Slough UK!