In 1966 I drove from Western Australia in my Mini to the Eastern States. The middle several hundred miles (this was before km) was not sealed. Going east a grader had just been over it and it was smooth. The Nullabor had occasional huge pot holes with branches stuck in them to warn you about them. Returning after six weeks the corrugations were dreadful for a couple of hundred miles. My foot brake stopped working and I spent a long time fixing it - which as you will realise was a very difficult task. When I started again it very soon gave up working so I drove the last thousand miles or so using just the gears and the hand brake.
Anyway I did drive to Mt Kosciusko which in those days you could drive to the top of. A couple were spending the night on top of Australia so I did so too.
These days you are meant to walk to the top so if you cannot walk you miss out on seeing these beautiful sights.