Once you get outside of the big smoke, unless you do not veer too much from heavily populated areas, your only real choice is Telstra. I live just an hour north of Adelaide and there are even black spots with Telstra. Any other provider might work on a Sunday when the north wind is blowing and you are standing upside down with you hat on backwards. Have a look Select your operator of choice and see if they provide service along you planned route, and still be prepared to get patchy service.
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