Well the semicircle of peaks qualify as a horseshoe, but I didn't start and finish at the same point. I'd originally planned to do a different clockwise horseshoe of Derryclare, Bencorr and bencorrbeg but when on top of Derryclare on a perfect day - bitterly cold and sunny - I felt it was too good an opportunity to miss doing the full Glencoaghan. This was in March 2010 and the north face of all the tops had a fair bit of snow remaining on them which was the only thing which gave me second thoughts. This snow, as I'd found out two days previously in the Bengorms, was frozen hard. I had been descending steeply between the Ben Creggan tops, and stepping on a long run of snow, found myself sliding uncontrollably down. I would have ended up down in the col had I not somehow been discharged to one side of this almost ice chute, managing to come to a halt on the frozen heathery slope.
Crampons and axe would have been the thing in the conditions, but I didn't have them.
The descent to Bencorr from Derryclare was the worst bit, but there were enough bits of soil and rock poking through the snow to make it possible to crab my way down.
I was using the Whilde and Simms "Walk Guide, West of Ireland" (1991, revised 1997), and they recommend a scree run as the easiest way down Ben Breen. This isn't exactly running, more a shuffling slow jog in the rolling scree as opposed to trying to resist the motion. This probably wouldn't be in a guide of more recent vintage, as it brings a lot of rock down though any descent of steep scree, however slow, is going to cause erosion. I have to admit it was great fun.
The next most difficult section was ascending Glen Gower. The heathery section that looked like it would normally be the way up was completely covered in ths hard frozen snow. Fortunately there is a rocky section to the left of this which is fractured intyo almost perfect steps enabling easy scrambling.
There are some steep rocky drops when descending to the road from Ben Lettery which need to be avoided.
This is undoubtly one of the classic Irish routes. Try to pick a good day to fully appreciate it.