Here is a list of all wildwalks take about half day (greater then 2 hours but less then 4) , they are ordered by walking time. Happy walking :)
Stringybark Ridge and Zig Zag Creek loop from Thornleigh Station
6.6 km Circuit, 2 hrs 30 mins
Hard track
Bumble Hill Dray track (Greta Rd to Forest Road to Yarramalong)
5.6 km One way, 2 hrs 45 mins
Hard track