Are you stuck on going to Coober? There is always Lightning Ridge in
northern New south Wales, much closer to the Gold Coast. There was
also a bit of boulder opal available there, as it is mined in Qld
north/west of the ridge. It’s our family preference. You could then
head back to Brisbane and fly to Alice. There is also the Ghan
Railway that heads from Adelaide to Darwin a couple of times a week.
Like the others have said, be prepared for some really hot days out
in the desert country. I’ve found some info that may interest you:
Kynoch coach services to and from Brisbane operate throughout the
week. Forcall 02 6829 0333 or 07 4639 1639.
Whatever you decide, hope you have a great time!