Spare tyre, belts and hoses, cpl of fuses and know your battery and alternator are working properly. Fuel is always good especially when you forget to plan your route properly. Water, for you and car, consider some fly wire over the radiator screen, loads of bugs to hit at various stages. Consider your lights, if you drive at night, better lights are generally essential in a featurelss landscape. Hard to say too much without knowing your route, driving habits and mechanical know how. The Bush Mechanics are good value though
http://www.bushmechanics.com/home.htm. MUSIC, it is quiet out there. Camp chair and some form of shade, kind of crap time of year to do the trip.
Tin foil hat and chemtrail data logger seem the thing to suggest about this stage

(btw, wtf is a chemtrail?)