To follow the Brenig archaeological trail, walk along the forest track on the east side of the reservoir for about three miles, then follow the waymarks back to the south along the forest edge.

Alternatively, turn right at Hafotty Sion Llwyd and walk up the track past the farmhouse to the forest edge. Go through a substantial gate and up a narrow but well-walked track between the forest and the fence. You are now back on the line of the Clwydian Way.

The track goes uphill into the forest, but the trees to the south were clear-felled in 2002 and the views were excellent. At SJ 00039 57014 turn right on a new forest road. At SJ 00257 57095 (the T junction with the next forest road) the bridleway goes straight on for about a third of a mile, across a minor road then straight on along a well-surfaced forest road. Down to your right is the little Clywedog Reservoir — not to be confused with the Clywedog Reservoir above Llanidloes. At SJ 01038 57561 the track divides. Take the right fork and immediately turn left following the waymark up a stony track. Ahead of you is a good view of the Clwydian range — which you will cross later in the walk.

Walk downhill, across another forest road and through a section of forest recently cleared in 2002 to the inturned angle of the forest edge under Bryn Ocyn. At SJ 02179 57877 leave the forest by a gate and walk straight on along the forest edge. At SJ 02637 57979, shortly after the end of the forest, the track divides. The Clwydian Way goes left over a stile but you go over the stile to your right and walk along the right of the field edge. The bridleway becomes a farm track past Hafotty Bach and a hollow lane round the farmyard at Cernyfed.

Turn right on the minor road and walk down past Rhwngyddwyafon (‘between the two rivers’ — the Clywedog and the Concwest). Immediately after the farm, take the track to your left, over a little bridge and up to rejoin the Clwydian Way through the woods.You are now back on the Mynydd Hiraethog Way as well, and you can follow its waymarks to Llanrhaiadr.

Follow the waymarked footpath down the valley, past some elaborate cast-iron gates. Eventually the track ends at a bridge which goes back over the river. Cross the bridge and turn left into Cyffylliog village. The church is worth visiting but you will have to arrange for a key. Cyffylliog also has a pub, the Red Lion, currently (2016) open evenings and all day at weekends.

Leaving the village, turn left on the Ruthin road, past the school and over the bridge. Walk straight on up the road signposted ‘Llanrhaiadr 4 miles’. This is a deep hollow lane, down under the roots of the trees. At the top of the slope, when the road bears right and a track goes left, take the waymarked footpath straight on. The Mynydd Hiraethog route is impeccably stiled and waymarked along the edge of the field, through a little wood and past Ysgeibion-fawr farm, though the path is very muddy in places.

Follow the waymarked path through the trees and up hill then bear left across the field ahead of you to the waymarking post at SJ 06651 59734, the gate above Ffrith-y-Ceubren. The Mynydd Hiraethog Way goes straight over the road above Ffrith-y-Ceubren and is waymarked across the fields. Follow the hedge along the next three fields then at the top of the slope cut across the field to the left and into the woods at SJ 06398 61032. Follow the track down through the woods. Turn left at the stony drive of a modern house but do not follow the drive down to the road. The right of way goes down the track to your left and over a stream.

Turn right on the road. In about 3/4 mile, at SJ 07271 61557, just as you emerge from the trees, a waymarked footpath takes you down a hollow lane to the left and back into the trees. Like all hollow lanes, this one is muddy at the bottom and could be difficult in wet weather. Cross the stream at the bottom, looking out for the charcoal-burners’ ovens to your left. Follow the path which bears up to your right. This is another hollow lane, very deep and boggy. You may find it better to look for the path above it to the right. At the top, cross the footbridge and bear right up another hollow lane to the road.

Turn right on the minor road, which goes through a golf course. Just before the back entrance to the Bryn Morfydd Hotel, turn left on a narrow metalled road. Walk past the front entrance to the hotel then turn right along a waymarked path. Walk down some steps and through thickets of laurel and rhododendron. Turn left on the vicarage drive and right on the metalled road down to Llanrhaiadr.