Heading north
Monkey Mia
Pinnicles...bit eastish..
Broome, Cable Beach..probably the warmest seas off OZ
The Kimberley Mountains..bring a radio..just in case there is a cyclone heading your way.
Heading South
Rottnest Island, by bike.
Fremantle
Margaret River,,great wineries
Esperance
Albany..western australia's original port
to the EAST... Kalgoorlie..the outback mining town.
As for going by bus,be prepared for a numb butt, because the bus distance are enormous..and if you are tall like me, well I would not fancy sitting in a Ryanair type seat for 8 hours...
Go out and have a ball, come back & tell us all about it.The weather will be fantastic.
PS: The ideal time to travel to north WA is between July /August - October