New MTB'er - Suggestions for good off road rides in the Hills District?

Fred Caterson reserve - a bit of single track and a bit of a hill
Rouse hill behind the sewage/waterworks.
H20 at Westlegih
Firetrails surrounding Cherrybrook

drive out to Wiseman's ferry
drive out to Marramarra NP
drive out to Wylde

Before they closed Quarry rd at Dural you could go through there to the back of Hornsby/Galston.

I'm near Castle Hill and I'll occasionally spin via the Smalls creek bike path out to Rouse Hill, but generally you have to ride on road for a bit before you can get offroad.

Subject to kids weekend activities could show you some of the tracks? PM me if you're interested.

Yes, there are a couple of firetrails that almost link together all around Cherrybrook and then continue to Westleigh. There are also some that are hikers only and so entail a lot of H.A.B.

Reasonably steep through the Berowra valley in parts so you get a good workout.

Hike a Bike - ie you are carrying your bike. At times through some of the hiking trails you have stairs and other exotic 'features' which make lifting a ~13kg+ bike somewhat of a challenge.

You'd think you could push your bike, but you still end up carrying it a fair bit.

When I've had a spectacular route planning fail like this then I tend to run through the HAB sections, you have to be quite careful when you come across hikers who obviously won't be expecting someone to run around a corner carrying a bike and looking a bit deranged [or at least that's my perception when I come across them!]