About one day's drive north of Perth is Monkey Mia around Shark Bay. Amazing coastline and dolphins. Not much in between though.

East is Kalgoorlie. People talk about it but basically it's just a big country town with some nice 19th century buildings and the world's biggest open cut mine. Not my thing.

But J Class Traveller is right. The pick is the Margaret River region. Easily accessible, great wine, food, coastline, walks, bush, and the Pullman Bunker Bay is good. In the same general direction but further out are Albany and Esperance.