Western Australia is a very sparsely populated state, and most inhabitants live in the area of Perth, in the south west corner.
A shame this enormous landmass has been maltreated by mankind in recent era.
Hiking the west of Australia, you should be aware that the rocks and soils beneath your very feet are groaning old, some 3 billion years. Nothing much happened here since that time. The soils are infertile and eroded.
For the hiker, the Stirling range east of Perth, a "recent" ply in the earth's crust, is an interesting region to explore. The Stirling Ridge walk however is one of the hardest to complete. A second, very nice trail, is the Bibbulmun Track, 964 km long, along the south west coast, which passes through native forest most of the time.