NRA - this may be of interest to you in realising where the SAAS country stations are located and the distance between ambulances in some cases.
http://www.saambulance.com.au/publicweb/pdf/SAAS%20Country%20Stations.pdfunfortunately there is no similar map for CFS stations located on the internet that i could find, but a lot of those gaps between SAAS stations are full of CFS stations.
also it may shock you to realise that a lot of CFS brigades do actually have a good response time, i could name quite a few that are almost always out the doors in 5 minutes or less, admittedly there are also a lot that i wouldnt trust to get a truck out the doors at all.
by the way, my brigade is located only about 15km from the CBD in the burbs and we quite regularly beat SAAS to vehicle accidents by up to 10 minutes.. little bit of patient care in the meantime doesnt hurt.