The Great Ocean Road , from Torquay to the 12 Apostles is a fabulous trip - ideally take a couple of days and have some accommodation booked to split the journey. The coast road sweeps around giving numerous spectacular views - sandy bays, small coves etc - you can identify equivalents to many British areas - Harry's rocks for example and it does feel rather like the Devon coast but on a larger (and for us at least) sunnier perspective.
We were trying to daytrip from Melbourne - but beware it is a long way "around" . It takes at least 1.5 hours to get down the large Bay even before you reach the coast. One way that can help is to go to Colac by main road and then head down to the actual coast near to the 12 Apostles then work your way back to Melbourne along the coast. This approach enabled us to see all the sites within one day but still with a lot of driving.
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