I'd be an ovenighter, after all that driving I always look forward to a shower, a quiet drink at the hotel and then off to dinner. But it's close enough for all to have the option of a drive back hope at the end of the day for anybody that would not prefer to stay the night.
This is a template plan from yeasr prior:
Meet at the outbound servo at the Westgate 10:00am with dep at 10:30am sharp
10:30am to 12:00 - Melbourne to Bells Beach approx 100km (1 hour 20 minutes), 30 min stop to stretch the legs and maybe walk on beach
12:30pm to 1:00pm - Bells Beach to Lorne, approx 25km (30 minutes), 1 hour stop for lunch
2:00pm to 3:00pm - Lorne to Appollo Bay approx 50km (45 minutes depending on traffic)
3:00pm Check in. For those that are staying the night check in to Apollo Bay accomodation, if weather is good go for a spin out to Lavers Hill and be back in time for drinks and dinner
Sulio