Adelaide > Sidney > Melbourn > The Ocean Road > Adelaide
What to do? Adelaide is a very student based city. It has a fun walking city center with nice food market and really fun places to go out. I did not spend much time there but really enjoyed the ambiance.
Sydney is often confused to be the Capital of Australia. And it is for good reasons. It is a really big city with a lot of malls, museos, concerts, tourists. If you like the business of a city and the abundance of options go for it. It is definitely worth seeing for it's great scenery and culture.
Australia had settlers about 2500 years ago and Dutch colons arrived around the year 1600. The culture and history is very influence by the colons cultures. You can find a lot of food from England and the Netherlands. The lost native history is coming back and brought back to life.
Even if it is a big city, Sydney has a lot of parks and scenic spots to enjoy the view of the sea and the fresh air. It can get really warm in the Australian summer and you'll enjoy your fresh and breezy places. I recommand the japonese garden. It is really fun and interesting but also quiet and calming.
To go from Melbourn to Adelaide we took a van with my sister. We drove along the sea in the fall season. It was rainny and windy but we had a lot of fun. It was very stressfull to drive on the left side of the road for the first time. I definetly had a lot of issues understanding the turning and roundabouts. We used an app to look for places to sleep at for free. We usually were pretty good with the spot we encountered. It was fun to share that moment with my sistyer and teach her how to wash your hair in te sink with a kettle or how to wash a van with toilet paper and the rest of the water tank (yes yes you understaood me). The drive is actually very agradable and easy. You'll encounter a lot of different places to stop and to visit.