We had a lovely time down at Claire's house in Barwon Heads with our 15-month-old. There's a great play room downstairs and a cot, highchair and a bath, which makes everything nice and easy if you have little ones.
It was just the three of us, but it'd be great for a larger family group too because there's lots of different spaces for everyone to have fun. It's also a nice bike ride from the house to the river and the town centre.