I followed the route described in Munster's Mountains by Denis Lynch ascending from Cumeenmore. He describes 2 routes, one climbing the gully in the SW corner of the coom and the second up the adjacent spur.

Cross the ford of the Gaddagh river at Lough Callee outflow continue until the marked loop walk turns back north, leave the path here and climb until you are vertically about halfway between the obvious boulder field at the end of the bone and Lough Callee. Contour here until you reach the stream descending from Cumeenmore, ford this and continue on it's West Bank until you reach the low plateau that rises from the West side of the lake. The route heads West up the steep slope that rises up the side of the truncated north spur. I kept well back from the cliff at the end of the spur, the ground is steep & grassy with rock outcrops that are generally easily bypassed. At the crest of the ridge there is a small col with great views into Cumeenmore and Coimin a Galasaitinn.

From here the route follows the crest of the ridge South towards Cnoc an Chuillinn and involves some straightforward scrambling on small steps and rocky gullies, but no more difficult than the Beenkeragh Ridge, and less exposed. The North ridge joins the main Reeks ridge 20-30 meters west and a little below the summit of Cnoc an Chuillinn. This is a very enjoyable semi-technical route up the Eastern Reeks, there was a heavy dew on the grass but this didn't translate to concerning conditions underfoot on the steep sections. Linkback: https://mountainviews.ie/summit/8/comment/23583/