If you're a car nut, & going to Oz, you must get to Bathurst, the greatest Motor Race track in the world.
Its about 132 miles west of Sydney, the largest city in Oz.
The track is a public tourist road, when not shut for racing, so you can drive around it, but only at 60Km, 35 MPH.
The drive out there is through some scenic coastal mountains, although you may find them more like hills. It is a good weekend trip, but can be done in a day, with out any trouble.
If you're in Sydney, on a saturday, get out on a Manly ferry trip. Its a pretty impressive harbour, & there will be literally thousands of yachts, & sail boats racing, & an equal number of hot water boats as well. Its quite a sight between midday, & 4 PM.
The Great Barrier Reef is well worth seeing, along the coast of north Queensland, but as its 600, to 1,000 miles from a major city, requires some time to get there.
If you like horses, come & see me. Don't worry if you've never ridden a horse, I've got some who've never been ridden, so they should suit you.