We flew that trip in 2005 for 75K each as an open jaw with a stopover and also two less than 24 hours convenience stopovers.

Routing was:
AA SFO-LAX, overnight at airport 8pm - noon
QF LAX-SYD, overnight in town 10pm - 4pm
QF SYD-CBR
drove CBR-MEL-ADL

return
QF ADL-MEL, FJ MEL-NAN
three days in Fiji
FJ NAN-LAX-SFO

This was booked about six weeks out but we were really lucky and it took about an hour and a half on the phone with the agent.

It helps to be fully prepared. Do your homework and have available at your fingertips every possible routing with flights if possible. Sometimes it takes a lot of trying and flexibility.