Thinking about a similar route to this for some time. I finally did it. Long, arduous and very hilly. Hills great for going down, not so much going up.
Starting from home in Windsor, riding out to the Gap starting on South Boundary Road, a fire trail with lots of ups and downs, a bit hairy going down but certainly not technical. Just lots of loose rocks and gravel. Bumping into a few other mountain bikers and trailer hikers (runners).
Creek Rd, about a dozen creek crossings (of course), one such about a foot (30cm) deep. So off came the clod-hoppers and walked through it.
Made it to civilisation. Still with plenty of hills to go…
Elevation profile.
Speed overlay.
A bit of mud about.
