Not surprisingly, surveying the arc of steep hills all around, when I tried to phone home to check-in there was no mobile signal in Llangynog car park or anywhere near: it would transpire that only the summits or highest slopes stand any chance of a service. This may be the ideal place for a lazy undisturbed holiday off the grid.

It was already very warm in the sheltered valley as I set off eastwards below Craig Rhiwarth, taking the narrow lane and soon departing left on the good path below the broken slopes of rock and quarry spoil, where the vegetation and young trees are gaining hold and softening the facade. The path turns into Cwm Glan-hafon and follows the west side of the Nant Sebon, and higher up where a small stream flows down on the left, I climbed steeply up to the source and curved southwards to the fort rampart, a clear line of broken rocks. Beyond this is the summit plateau, a broad flat area with the cairned summit to the west and a lower rise to the east.

The day had turned disappointingly dull after the sunny start, but the tops were clear and the views pleasing,

I made a pathless descent northwards and joined a fence ascending over the shoulder of Moel Crynddyn where I found a ruined stile with "Pistyll Rhaeadr" carved into the wood, no doubt intended for walkers ascending through the forest from the west and heading for the famous waterfall. I crossed to the west side of the fence and followed the clear track NE alongside it to a fence junction at its highest point where I turned westwards heading for Post Gwyn (this fence is barbed: stay on its south side to avoid gymnastics later despite the boggy bit at the start).

The broad east ridge of Post Gwyn is a little wet and slightly rough at times, but trivially easy compared to its infamous west ridge and I made quite good progress to the summit cairn.

The plan now was to descend to the Afon Disgynfa and follow it to its source, bypassing almost all the west ridge. The good path from the Disgynfa to the bwlch between Post Gwyn and its west top is easy to spot in ascent, but this time in descent I obviously missed the direction by a fraction and near the bwlch I was awash in a sea of truly horrendous terrain where every step must be carefully tested. Lurching along in roughly the right direction I eventually spotted a sheep's head peeping up that, for once, really did make a good navigation beacon - even they never venture into this terrible morass. Sure enough there was the path and I reached the infant river.

Hugging the south side of the Disgynfa and ascending gradually towards the source is not exactly easy at times, but there is sporadic evidence that a few walkers have attempted this idea before, and not all the little fragments of trail through the reeds were made by sheep. The valley is wild and deserted with a charm of its own.

A final short section of moderately rough terrain above the source brought me to the ridge path from Moel Sych. Much of the lower section of this path has been laid with duckboards, making progress swift to the road at Milltir Gerrig. The familiar track on the far side gave its grand view into Cwm Rhiwarth and I continued over the footbridge a little farther on.

The bridleway southwards follows a wet tractor track at first, but a little higher up a better beaten line has been established alongside the Nant Calch, although still rather wet in a few places. Even this line breaks up eventually and the key is to wait until the crossing fence comes into view on the broad flat horizon and aim for the stile. Here the bridleway diverges: I took the eastern fork, relying on careful mapwork to locate the heads of the two small ravines that are initially out of view, where the bridleway suddenly becomes an excellent track on the ground. A long but rapid descent brought me to the road in Cwm Pennant.

I walked along the lane into Cwm Llech following the line of the Pererindod Mellangell (PM) walk, parts of which we covered on our Tanat & Efyrnwy backpack. A huge vegetated rock slab on the left was our nearest approach to Pistyll y Gyfyng and so it will remain, it can still only be heard and not seen. At SJ020246 where a PM waymark directs left through the gloomy trees to the infant Afon Goch, I took the unsigned public footpath uphill on the forest road to Llyn y Mynydd, that despite its name is a lake in a working agricultural setting of cropped grass and densely grazed by sheep, though not entirely without charm in the right conditions - this would be the next morning in the early light. A couple of fishermen were casting their lines on the shore, they had passed me earlier in their 4x4 on the forest road.

A good track continued up the slopes of Trum y Fawnog that took me most of the way up, and I continued on easy grass to find a good pitch, very welcome after the energy sapping rigours of Post Gwyn and the frequent bog dodging. A pleasing sunset rounded off a hard-fought day.

The dawn sky signalled a sunnier day ahead and I heard the frenzied bleating sound of a sheep roundup near the lake, they evidently start work early here. A while later they were gone and I struck camp, retracing my steps back to the lake for a better view: it certainly seemed much more attractive in the warm early light.

Just below the dam a forest road climbs southwards and turns through the forest to rejoin the PM walk at a waymark indicating a good path through the saplings to the forest edge at Waun Llestri. A bridleway runs along the forest boundary, typically wet on occasion, to the second Dewey summit of Ffordd Gefn (Bryn Gwyn). Technically the spot height is just inside the forest but the ground seems barely higher, I didn't do the purist thing and fight it all the way.

When the trees end, the next section of the path gives splendid views into and over Cwm Dwygo and Cwm Pennant to the Berwyn ridge beyond. The path reenters the forest and becomes a forest road (watch out for a waymark at SJ050246 bleeding off left and take it to arrive at the main track junction). A forest track descends steeply to Llangynog giving a final view of Y Gribin & Rhyd-y-felin.