Looks like a good trip out. Always liked the look of the NSW high country from the videos I've seen.
As for fuel, 2l plastic mini jerry cans are quite handy and easy to strap down, especially if you make/buy a securing plate. Otherwise a Rotopax setup is the way to go, but pricier obviously.
Spares is an interesting one - where do you stop when drawing up a list? You�re probably unlikely to wear anything out in 5 days (providing it�s not on its last legs already), so no need for throttle/clutch cables etc. Spare tubes and levers are a good idea though. You�ve just got to think carefully about what accidental damage might prematurely end your trip. Personally, I would always take a few metres of 16.5A cable, fuses, some Scotchloks, terminal blocks and insulating tape etc. Just enough stuff to sort out an electrical fault, like for example bypassing a knackered clutch or side stand switch � they are simple things but can result in a non-runner/non-starter.
Top of my list of spares is always a sh!t load of cable ties!