From the OP:
C182, mid December. Looking for the most efficient way to get there and back. VFR.
At that time of year consider heading south, Merimbula, Mallacoota, Lakes Entrance, Phillip Island that'll keep you away from the Qld coastal thunder stormies.
Mate he's going Bankstown - Ayres rock, not bloody Brisbane-Bundy-AYE. Where do coastal CBs come into it?
UP:
BK
SCO for fuel & coffee (although DU a straighter line)
BKE - fuel
BDV - fuel
AYE - fuel
BACK:
AYE
CBP
BHI
PKS
BK
Northern route or southern route as winds, fuel prices etc dictate. I agree with the others, though, will be a hot (*) of a trip