Clubs in VK5

[VK5TM]

The closest active one to Gawler would be

Elizabeth Amateur Radio Club Inc.
The Scout Hall, 68 Mofflin Road, Elizabeth Grove 5112

http://www.earc.org.au:82/EARC/

As for Osbourne, probably this one would be the best bet

Amateur Radio Experimenters group
Fulham Community Centre, Phelps Court, Fulham

https://www.areg.org.au/

There is one club in the Barossa if you want to go the other way, but not having lived in town for a long time, I forget how far the drive is.

After that you are going much further south or up into the Hills.