The likelihood is that things would get worse the further you move away from the metro area, plus the number of schools (ie your potential choices) decreases. There are probably some BE members on here who are perfectly happy with the Mandurah/Rockingham/Bunbury state high schools, so hopefully you will hear from them too. Have you looked up the different schools on the My School website?

If it was me, I'd head closer to the city, and if you have to stay SOR, aim for Willeton, Rossmoyne, John Curtin or Melville SHS catchments.