There's more to it than South Australia,New South Wales,and Western Australia.
Murray Bridge,and Mt Gambier are in South Australia. Premier and Avalon are in the neighboring State of Victoria. Archerfield,Toowoomba,and Maryborough are many miles to the Northeast in Queensland,then head south again to Lismore in New South Wales. Then is the break where there are other big races on,the Sprintcar Title,and the Grand Annual Classic, the Kings Challenge,and surely some races in Sydney too,before they head west to Esperance,Bunbury and Kwinana in Western Australia for the final World Series Sprint cars rounds.
https://www.worldseriessprintcars.com.au/calendar