For the oombie grog runs, you'll need a lot more capacity than a B737. I recomend cross hiring a few globemasters or C5 galaxy or for special days such as PAY day possibly an AN225. They would still manage to overload it I'm sure.
S/E cessna - very good mate, hvent laughed that hard in a long time.
# as for a twin job maybe golden eagle in Karatha or Derby, might require a little on 206s first but reasonable pay and conditions. Or try OZwest Karatha too.