Hi dnaylor,
EDIT: Damn it, I've just realised that I have written this reply starting at Stanwell Park. Apologies for the error.
I've walked or ridden nearly all of those tracks/trails between Stanwell Park and Appin. Some of them several times.
I had a look at the gpx track from the federation track website. Holy cr*p, who mapped that track out, what a shocker. Who ever mapped this has never walked it.
The best way to do the section from Stanwell Park to the Princes Highway is along the Forest Track. Their map appears to use the fire trail network to the west of this track meaning many of the good views along the way are missed. Pity.
The section from the Princes Highway to the 10a fire trail crosses catchment land. There are signs all along the roads in that area. No one is allowed in this area without special permission. If it was me doing this section I would head north along the highway (past the Boomerang golf course) and then west along Darkes Forest Rd to the 10a fire trail (it's the fire trail 50-100m before the Maddens Falls trail car park). As fas as I am aware this is the only legal way to do this section.
The 10a to 10b section is fine. I like the track down across Iluka Ck.
10b to Appin. There is so much wrong with their route. After heading north along the 10b trail you are advised to head west before turning south towards the Appin-Bulli Rd. Where do I start with this disaster. The trail heading west from 10b is the old service trail for the abandoned coal mine power lines. I've investigated this trail from a couple of angles and decided against trying to follow it as it's a scrub fest (trust me, I've done a lot of off-track in Dharawal NP). There really is no need to head south and cross the Appin-Bulli Rd. Also, I am not sure of the legality of firstly, traversing the cataract scout camp and secondly, using the trails from the scout camp along the Georges River to get to Appin (the land on the south side of the Appin-Bulli Rd is catchment land).
My route from 10b to Appin. Head north along 10b until you get to the 10r trail sign. Directly across the road from the 10r sign is the start of the Seven Creeks Way. It is overgrown but not hard to follow. Just continue to head west till you get to the colliery road. Walk north along the road (sticking to the fence as the road all the way to the Wedderburn air field is leased to the colliery and is technically private property). Continue past the gate at the end of the bitumen onto the dirt road. Look for a clearing at*: -34.210152, 150.822942. The main fire trail starts in the NW corner of the clearing. This fire trail heads west till it hooks around to the south and crosses the Georges River. After crossing the river look for trails on your right. Walk up the trails to Appin. Admittedly this is not as scenic as the federation track suggested route but it is doable.
Any questions please don't hesitate to ask.
Michael.
* I need to check if this is the right spot. I will go through my archive of mtb rides in that area and check. My memory is not as good as it use to be.
One foot in front of the other.