Naracoorte is 92.7km, about 1.1hr, dependent on loo stops, wildlife spotting and the amount of chatter coming from the back seat. It’s a scenic drive through the Western flat, true farmers country.
So long as everyone has behaved (partners included) you may have enough time to have a look in Naracoorte Caves or at least the fossil museum. The bunkhouse here is very affordable for the night, $75 for 2 adults and 4 children. There are BBQ facilities there if you feel like a few snags for dinner or go into town. Pizza, pub food, it’s all pretty good!!
All up you’ll have about 3hrs left of driving to get to Port Fairy, so take a few hours in the morning to experience the caves. If you are feeling adventurous there’s caving tou