I've gotten the flights booked so here's the plans:
Melbourne - Canberra 29/5 08.10 (arr 09.10) <- Virgin Blue Flight
Canberra - Melbourne 31/5 20.00 (arr 21.05) < - " " " " " '' "
Melbourne - Tasmania 2/6 20.00 (arr 07.00) <- Spirit of Tasmania Boat
Tasmania - Melbourne 6/6 18.15 (arr 19.25) <- Virgin Blue Flight
Great Ocean Road 7/6 - 9/6 <- Hire Car
Melbourne - Adelaide 9/6 20.30 (arr 05.20) <- Greyhound Bus Overnight
Adelaide - Alice Springs 13/6 12.20 (arr 14/6 13.45) <- "The Ghan" Train
Alice Springs - Darwin 18/6 11.50 (arr 13.50) <- Quantas Flight
Darwin - Cairns 24/6 06.45 (arr 11.00) <- Quantas Flight
Then we are planning to get an unlimited stop bus pass for the East Coast from Cairns - Sydney, and planning to leave Sydney for Auckland on the 15/6. [EDIT - The 15/7!]