I learned of this excellent walk in the Upper Blue Mountains from a couple I met on the summit of Mt Hay. It’s possible to continue on over Mt Hay to a rocky outcrop called Venus Tor, and there are excellent views over the Grose Valley for most of the way. Plus you’re unlikely to meet many/any other hikers after Mt Hay. The drop down from Mt Hay is very steep, and then passes through mostly heath and scrub to the tor. Easy enough walking.
At first follow the route to the summit of Mt Hay from the car park at the end of Mt Hay Road, and walk on 5-10 minutes to a spot with views out towards Venus Tor; I posted on that walk here. The route descending from Mt Hay is at first marked by cairns, and drops very steeply down to rocks on the edge of the Grose Valley. You continue on over the rocks and along a mostly distinct route to the tor, with cairns on occasion where the route is a bit less obvious.
Climbing up to the summit requires walking to the right along a narrow but wide-enough ledge at the base of the tor, and then there’s easy access to the upper sections. Here’s a link to Venus Tor marked on Google Maps.