If you can manage 4 days, how about:
Melbourne -> Torquay
Torquay - Apollo Bay via Great Ocean Road (lovely ride on a week day without the weekend warriors)
Apollo Bay -> Colac
Colac -> Ballarat. Check out the Goldfields tourist stuff
Ballarat -> Heathcote (some lovely back roads through the hills)
Heathcote -> Echuca. Check out the old paddle steamers, maybe book a river cruise
Echuca -> Hay (lots of not much, but gives an idea of scale
Hay -> Temora (Supermarine Spitfire at the aircraft museum, but not sure if it's open)
Temora -> Bathurst. Do a lap or 2 of the Mt Panorama race circuit. There's a 60 km/hr speed limit and policed heavily
Bathurst -> Lithgow
Lithgow -> Kurrajong -> Richmond (Bells Line of Road, lovely on a bike)
Richmond -> Penrith.
Thomas will know Victoria much better than I do, since I really only go to the All British Rally and BSA Nationals. He is sure to have some great suggestions.
If you're limited for time, cut out the Great Ocean Road (which would be a shame) and go direct from Echuca to Temora.
We're taking a similar route home from Halls Gap via Echuca, with a couple of detours.