Followed the GPS along the Great Ocean Road and took the inland route to Avalon Airport; you can see

AVIS has many branches, most airports have one, so it's very convenient. Returning the car is easy; just park it in the designated area and drop off the key. But make sure to return it with a full tank. They will try to sell you insurance similar to a no-deductible policy. If you've already bought full coverage insurance from your home country, you don’t need it. Otherwise, it’s smarter to buy it, as you might encounter wildlife like kangaroos on the Great Ocean Road.