Thank you all for the replies!
Definitely a lot of information to take in, but from what you've all told me, it seems like RA-Aus would be the best approach for me, given the many components and endorsements that will carry over to an RPL for the PPL pathway in the future. The paperwork part still seems a bit muddy, but I'll figure that out as it comes. As long as they carry over, that's all that matters.
So, it's looking like I'll end up going to the Adelaide Soaring Club then, which would offer both gliding and RA-Aus training, but I don't live too far from both Gawler Aerodrome and Parafield Airport, so I should be able to converge paths in the future without too much difficulty.
Cheers again for your help, and if I do run into anyone at the aerodrome, let me know - I owe you a beer as thanks!