QF offers a "walkabout pass" which is only sold outside of Australia as an add-on to an international arrival into Australia on QF -- quite a good deal. There may be similar offers available from UA/DL/VA etc. ... check with whatever airline you are flying into Oz. Getting 5 award tickets on the same flight can be hard esp. for ASP which often sells out on some dates and has limited service. MEL-SYD you'd have no trouble, but MEL-ASP-CNS can be very hard for some dates even for paid tickets (all depends on your travel dates and flexibility -- presumably zero if you have a planned itin).