Y Gamriw is a 604m hill above the Elan Valley and is topped by a trig point and a cairn / stone shelter. It feels like a very remote hill with tough terrain on the approach and I did not see another person anywhere near it or the fairly nearby Gorllwyn mountain.
The top is interesting, and the views back towards Gorllwyn and Drygarn Fawr offer a tremendous sense of scale so I am glad I walked onto this hill. What is also good is that there is a path back down to the car from here.
Yes, the path is frequently boggy, but it is slightly better than the random slog that most of this route is. When you get back down to the valley you are treated to carpet like grass and then stone tracks.
This was the final hill on a long day, it is worth doing, but it is not easy.