I drove from Perth to Melbourne
And if worst comes to worst slash wrists
A couple of years back in my VS Caprice, 3.5 days door to door. Didn't miss a beat. Long distance cruising puts very little stress on a car/engine. Its all the stop start stuff that does that
Full service. Go round and visually check all lights, bolts, tyres, make sure your mudflaps are tight, wheel nuts, all that sort of thing. You know, just take a beer and slowly move around your car and LOOK. LOOK!
Take spare tyre, tools, plugs, belts, enough coolant for a FULL change. Fix a flat in case of a second blow out. No point being stuck on the side of the road because of a cheap belt or you havent hit the next roadhouse to get your flat fixed.
Take spare DRINKING water. It can get very hot out there, especially if you waiting for a tow. 2 litres per person is a good guide. You may be waiting for a few hours. Broad brimmed hat.
Pump your tyres up a bit. I was at 50PSI coming over, but that was a fully laden car at high speed.
Avoid dusk and dawn driving and do NOT drive at night unless you really really have too. Make sure when you stop for fuel, you get out, stretch, have a coffee and something to eat. You know. Take your time. Stop and check out the scenery when you can. Its rather pretty
Common sense and you should be fine. I thoroughly enjoyed it. Turn on cruise at speed limit plus 10, climate, stereo and start singing.
*edit*
Oh and if something DOES go bang, its like an unwritten rule out there. Someone will stop for you and at least let the next roadhouse know you have broken down and they will send a tow truck. Most of them have rooms so if worst comes to worst you can stay the night. Holden parts are plentiful and even if it is something MAJOR, it can be thrown on the next truck coming over.
Have a blast dude