I went through this two odd years ago, the things I found when going from RAA to GA were;
1. Getting used to a heavier aircraft, A C172 handles a lot different to a Jabiru or sportstar. Round outs and holding off took some time to get right.
2. Navigation & planning were a lot more in-depth. This probably should have been covered in RAA but wasn't.
3. Controlled airspace - the radio work, read-backs, clearances, ground control etc. took a while to get familiar with. But you don't have to do Controlled Airspace if you don't want to, it is something you can add later.
My advice is fly around in RAA for 40 odd hours, make sure you can stick to an altitude (try for +/- 100'), keep to a heading (try for +/- 2 degrees), enter and depart circuits properly, conduct square circuits, fly to the hemispherical's, navigate without a GPS, decipher a TAF, ARFOR etc. It's cheaper to get your flying up to PPL standard in an RAA aircraft, and when you are at a good standard then go for your PPL.