The big red kangaroos are not as far North as where you will find the Buffalo. They are desert animal and live in dryer climates. We sometimes see them near where I live but usually in droughts when they move into the hills for fodder because of drought.

The Eastern (and Western) Grey kangaroos are more common.

To find either of these you will need to travel further South.

The Top End will have wallabies and maybe Euros. (Bakes can you help out?)