What are the chances of seeing them? I have seen rock wallabies on Magnetic Island and close to Mareeba in North Queensland. In both places, they were very habituated to people and it would be hard to miss them.
@PAT 100% chance! They are all over the rocky hill right beside the gardens, with a trail leading up from the gardens' cafe. The wallabies are very relaxed around people (although not allowing too close an approach), and I would see them at any time of day I was there.