I'd make a standby car reservation just in case. A few years ago, my partner and I had stayed overnight at Katoomba or thereabouts. Terrible weather and visibility (a 1 May IIRC though November should be much better). Just as we had given up hope of seeing anything and were on the highway back to Sydney, the weather cleared up so we turned around and had a great sunset view of the 3 Sisters. There are a few other vantage points which may be a bit remote and long to walk to. Not sure if the bus mentioned goes to these points.