I was finally able to ride to the John Hunter Hospital via Richley Reserve last week, after the comments on an earlier post alerting me to this possibility. I was hoping that this would be easier than hauling my bike up a flight of stairs, and possibly a bit quicker.
It is certainly a more scenic route and riding through the bush, or pushing my bike up the hills, was easier and more pleasant than the stairs. In summer it would be even more so, due to shade from the sun.

From Google Maps

The problems I encountered were that I got lost going in both directions. I took a different route each way, both times intending to take the shortest trip through the bush, according to the map. I had my iphone with me and using it could locate my position in the Reserve, but there seemed to be a variation between the paths marked on the map and the actual paths. It was not a huge problem however, I only had to backtrack twice, and if you head uphill you will eventually arrive at Lookout Drive and if you head downhill, you will arrive in New Lambton. There are some deadend tracks though, which is where I encountered the problems. On one such deadend I encountered this lizard, which I wouldn’t have seen had I been riding …
The paths are quite wide and well defined with smaller and more rugged side paths going off them. Riding was never a problem. The bush land setting is beautiful and the tall canopy of overhead trees gives a sheltered quality to the ride.