Yesterday (which was meant to have better WX than today - doesn’t look like it now) I climbed Mynydd Mawr, GW/NW-026, starting from Rhyd Ddu and taking the train to Plas-y-nant. Coming back down to Rhyd Ddu by the south ridge then makes a great circular route. If you could mesh with the timetable to take it in the other sense you could finish with a Mws Piws or ice cream on the train! Highly recommended either way. I’ve uploaded my GPS tracks to the mapping project.
Thanks to Iratxe for S2S and to all the chasers.