Ideally we could find somewhere which is within a few hours of Sydney, and somewhere which is reasonably accessible (don't mind a short hike). Somewhere which wouldn't be too busy, or at least have some space where we can pitch a tent

We were originally considering doing the hike from Bundeena to Otford but I know that the North Era campsite there is booked out.
Does anyone have any other suggestions as to what may be a good campsite?