Kathy, G'Day.
It's true that all visitors to Oz require a tourist visa. This can be processed on line through the CRS systems very quickly and easily at no cost. Check-in staff can do it as well, but it's best to have it done and in your booking once your booking is in place in the CRS.

As for RV's, the best option will more than likely be Britz. Specialists in that field down here.

Cheers.