Starts at the west end of Lough Muck. There are a couple of laybys around here to park. Route starts with a bog track that leads through a fence with a makeshift gate to a bridge over the Culfin river. This river is quite wide and not otherwise crossable. Benchoona looks quite formidable from here, with a line of black cliffs protecting the summit.
The track peters out soon after the bridge, at a working bog. The first half of the ascent is over rough but not overly steep ground. I stayed close to the stream that comes down the face of the mountain. At about the 250m contour, there is a slight drop into a lovely mini-valley with a stream running west along it. From below, I had thought the best bet from here would be a somewhat grassy patch among the cliffs to the left of the deep gully in the centre of the photo, and from here this still looked the best - or perhaps only - possible ascent.
The final ascent route is on almost the extreme left of the photo above. This comes out at the summit area between Benchoona and Benchoona East Top. One thing that struck me while scrambling on the steep upper slopes is the difference between Benchoona and its neighbours in the Bens and Maamturks. The rock in the Bens/Turks tends to stay much drier than the surrounding grass/bog, and free from vegetation. The rock on Benchoona is wet, slippy and slimy, with wet grass and moss sprouting from every crevice. The mountainside also appears to be home to a very large and well-hydrated slug population, which didn't really add to the pleasure of the ascent, from my point of view.
The slope I was on wasn't quite as steep as the neighbouring slope that's on the left in this picture. But it gives an idea of the steepess of the ground in the area. It was slow work, searching for the most feasible route over slippy, sometimes near vertical rock and ground so soft that bits of it became detached under my feet a couple of times. There was always a fairly straightforward option in the end. I'm not sure I'd do it again, unless maybe after a really
dry spell. But it was quite rewarding to do it once.
I wandered around the top - now in mist - a bit, taking in the two listed summits. I had decided to definitely not take the same route down as I had used to get up. Earlier I surmised that if initially I took the more popular route north-west from the summit towards Lettergesh, I could turn north/north-east once I was below about the 400m contour, and miss all the cliffy parts. I did this, and it worked quite nicely for a comfortable and pleasant descent, except at the very end where the dogleg in the route results from me heading for a working bog that wasn't the one I had passed on the way in. There was some unpleasantly swampy ground around here, even after the drier than normal summer. This aside, a similar line to this might be a decent option for ascent as well.