Melbourne has a place that is called Sovereign Hill. For those who do not know what it is, it's described on Wikipedia as an "open-air museum". Basically it has old style buildings, horses and carts and there are activities for kids. It's a great place to go for families.
What is Sydney's equivalent?
We had Old Sydney Town just north of Sydney.
Back then we had lots of places - Wonderland, Paradise Gardens, O'Neills, etc. These days we have almost nothing.