You're on your pilgrimidge to Uluru (known to the locals as The Rock).
You are looking for a medium sized cache. There is enough room for a travel bug or two and some swaps.
Uluru, or Ayers Rock, is a massive sandstone monolith in the heart of the Northern Territory’s arid "Red Centre". The nearest large town is Alice Springs, 450km away. Uluru is sacred to indigenous Australians and is thought to have started forming around 550 million years ago. It’s within Uluru-Kata Tjuta National Park, which also includes the 36 red-rock domes of the Kata Tjuta (colloquially “The Olgas”) formation.