It's very good and the best part is that it is downhill from Hill Top to Penrith. Have a look at the appropriate bits of the "Longer Loop" or "Longest Loop" from here
https://ridewithgps.com/events/124957-g ... ember-2020. There is some road works on the Northern Road which at times prohibits bicycles but the detour through Glenmore Park avoids these, avoid Mulgoa Rd as it is narrow, few shoulders and too fast motor vehicles, otherwise most other roads are ok to good.
I have used this section quite a few times but the most recent about 6 months ago shortly after the fires that affected that area. There was a lot of branches and bits of tree on the road but hopefully cleared by now. It is mostly minimal width with a bit of traffic especially weekends / Sundays but not much trucks
Nice cafe at Hilltop, the shops are just off the road (a parallel road to the west)