Drive slowly and get out of the car often. The headline stops are the Twelve Apostles, Loch Ard Gorge, Gibson Steps, London Bridge, and the Bay of Islands, but the Otway rainforest breaks up the coast beautifully.
Surfers should allow time around Torquay and Bells Beach. Walkers can mix short waterfall tracks with beach stairs and cliff-top viewpoints; just keep an eye on tide, wind, and cliff-edge signs.