I broke in my car on a road trip for work.. VB to Baltimore/Philly and back. I agree on the pocket bit.. and on the "shit now or shit when mother nature decides you shit" part..
All in all though its a very comfy car to be in for long times. The seats are very comfy even if the ride is sporty car tight.
Lots of water! It was mentioned above but very much worth reiteration. You'd be surprised how quickly you dehydrate when driving. Stick to snacks that are low in sugar and higher in protein. They'll keep you awake better. I like cliff bars.. but they're an acquired taste.
clean the inside and outside of the windows THOROUGHLY before you leave. And check all the other stuff listed above (oil, coolant, windshield washer juice. etc)
Bring good tunes and enjoy the seat time!