Don't rely on the closing times of outback servos. If business is slack they may close an hour earlier than the stated times.
An ST1300 carrying 5 litres of fuel should be able to travel from Port Augusta to Darwin refuelling at 24 hr servos - Port Augusta, Coober Pedy, Marla, Alice Springs, Tennant Creek, Katherine and Darwin.
Good to see you at Urana, Craig, and a good RR as usual.