I have driven from adelaide to sydney, think I only had to fill up once without 98RON, and even then it was 95RON, wasn't too bad. As for stone chips, I attached some mesh cloth (kinda like shadecloth) to the front of the car, didn't look too good but it certainly did the job...... and didn't scratch the paint either. Also stopped every now and then to clean the bugs out of the grill/ducts etc.
just watch out for the rozzers on the Hay Plain, patrol car was travelling in opposite direction to me but once they saw the 'line they did a u turn, chased me and pulled me over, for no reason.