and you want to do Sydney, Melbourne and the reef then I suggest you fly everywhere. Note that you'll lose a day on the flight to Australia. The other "big" attraction is Uluru (Ayers Rock), there are direct flights Sydney-Uluru, Uluru-Cairns and Cairns-Melbourne using a combination of Qantas and Jetstar. When you do the reef you'd fly into Cairns but I suggest staying in Port Douglas about an hour up the coast. Much nicer town and a choice of several smaller reef tour boats (avoid the Quicksilver behemoths).
For itinerary ideas go to www.flyertalk.com, select Travel&Dining:Destiantion>>TheWorld then select AustraliaNZ&SouthPacific.

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