The one thing we did was make sure our vehicle is up to the trip. Make sure it has had a recent service, all squeaks, rattles and oil leaks are investigated, to make sure they are not terminal.
I carried two new air cleaners. I replaced one at the top and one back at Cairns. This included blowing them out with compressed air every afternoon. I also carried, radiator and engine stop leak (never used) and extra serpentine belt, which I used on SteveandViv Paj, to rescue them back to Coen. Worked a treat (Patrol belt used on a Paj). Sorry Paj owners
CT - We used plastic boxes to carry similar items, including clothing, cooking gear, so you didnt have to go looking for them.
Food - we chryovacked our meat from Tweed, for most of our trip, but then bought reserves from Cairns and Bamaga supermarket.
Fridges - We took two - a 50L and a 60L fridge. One in the patrol and one on the CT. I designed a shelf for both fridges, that allowed me to put food on the bottom and drinks on top. Worked a treat.
Fresh fruit & Veg - We brought with us a styrofoam box with us and placed all the fruit & veg in the box, linned with news paper. It worked well, but we lost some veg. You have to watch the heat.
Loo - We purchased a thunder box loo and it worked a treat. The biodegradable bags that came with it also worked well and didnt soil the inside of the toilet. I had my two daughters paint the top, so they got used to being around it. When it came to using it the first time, there were fights, but the two girls.