This route is generally ok except for the descent to the road at the end, east of the lake, which was over steep blocks covered in heather. Would recommend either trying around 100m further south or 600m further north than where this track emerges onto the track.
The start follows the correct route of the Duhallow way which was changed around 2011, and is only reflected in the latest OS 1:50,000. As of late 2012 the Duhallow way near the start of this walk is not correct on the 1:10,000 OS map used by this website. Note that there is an access issue to the NE of Caherbarnagh which you will run across if you follow the old line of the Duhallow way.
The ground between Caherbarnagh and Knocknagowan is very rough in places, however has a quality of isolation and wilderness seldom available. The route to Knocknabro West Top is similarly rough with no paths.
I am told that the route due west from Knocknabro is a relatively easy way to descend to the Duhallow way.