Would strongly recommend to stay overnight. Cos driving back to Melbourne is at least 2 hrs at night. U probably won't have had a proper dinner also if u been at the penguin parade.
I would stay one night then drive out the next day. Which is what I'm doing anyway.
I have 8 days on the ground and it's more than enough to do both Philip Island and the GOR until port Campbell region. But depends on whether u want to spend any time in Melbourne City itself.
Driving from Philip Island to the start of GOR at Torquay takes about 3 hours+.
Thanks for the pointers!
Yeah, where possible I normally avoid night driving while in overseas. The only time I think i drove was from Brisbane airport to Gold Coast after flight landed around 6+pm.