On a beautifully clear October morning (7am) we headed to Wentworth falls (2 h from Sydney by train) to do the National Pass (preceded by the Charles Darwin Walk). I have previously done this walk about 7 years ago (in 2009) and I think it's a medium-hard, but very enjoyable walk that surpasses Katoomba by a LOT. It's much less crowded and the views of the canyon and waterfalls are spectacular. Wentworth Falls itself is huge, and you even cross the falls multiple times throughout the walk. Here are some photos from the walk!
A great looking canyon.
Looking down from the top of Wentworth Falls
Some awesome rock layers that I need to find out what they are made of!
The surroundings went from dry rocks and pebbles like this to very wet rainforest-type conditions
Weeping Rock - great to swim in summer, but probably the coldest water I've ever dared to enter. Painfully cold...
This walk is medium-hard (but definitely doable for most beginner hikers) and really enjoyable with great views along the whole way. I recommend it over Katoomba if you're only in Sydney for a few days.