I wanted to have an anniversary getaway near the Blue Mountains, but pretty much all the places have a minimum 2-night stay, which didn't work for me.

Well anyway, these are places that seemed promising and a bit luxurious:
 * https://www.bowercottage.com.au/pricing-guide
 * https://www.thekyah.com.au/the-king-room
 * https://www.eagleview.com.au/