Collarenebri Bore Bath is a free public soak on Wilson Street, using warm mineral water from the Great Artesian Basin. It is a modest facility, but after a long inland drive that can be exactly what you want: hot water, open sky and no performance.
Check current opening times before counting on a soak, since bore baths close for cleaning, maintenance or seasonal reasons. Bring swimmers, a towel and drinking water, and keep visits short in very hot weather.