My 23-year old daughter and I will be in Sydney for a week in April, and have planned a one night stay in Katoomba. We are planning to take the train early one morning, spend the night, and return to Sydney by train the next day, as late as necessary to see as much as possible. We are quite fit and like to hike. We aren't really interested in just going to lookouts with masses of tourists. What are the must-see places and hikes we should aim for?