(S/E)There is no car park in Bethesda, but the best option is to leave the car by one of the roadsides to the east of the village. The walk-in follows pathless terrain across a grassy valley, following the course of the Afon Caseg (river) with the objective of climbing Yr Elen first via Cwm Caseg, home to the tarn of, fittingly enough, Ffynnon Caseg. Typically of the Carneddau, it is necessary to walk across long grassy stretches to reach more interesting terrain later on. The less interesting phase is well worth it once the climb up Yr Elen starts gaining altitude in earnest and the jagged ridge leading to the summit is reached. The route heads up Yr Elen with the oblong shaped Ffynnon Caseg below to the left. Yr Elen is an "outlier" if doing a long traverse of the Carneddau end-to-end, but it fits in neatly as part of a circular route such as this.
(1)The summit is a mixture of grass and rocks with the highest point not being immediately obvious as there is no trig point or cairn; rather unusual, given that this is one of the highest peaks in Wales. The ridge of Mynydd Du, leading up to Carnedd Dafydd, can be seen across Cwm Llafar to the south west from the summit area. An obvious path now descends down into a dip, passing near the edge of Cwm Caseg to the left before rising steeply again up a rocky slope to lead to the similarly rocky Carnedd Llewellyn summit plateau. A wind shelter appears near the summit of this, the fourth highest mountain in Wales, and it offers some respite in the event of adverse weather conditions.
(2)The Glyderau appear to the left on the descent down to the next dip, Bwlch Cyfryw-drum, before the gradient climbs more gradually along the Cefn Ysgolion Duon ridge to Carnedd Dafydd, the third and final summit, and the third highest mountain in Wales after Snowdon and Garnedd Ugain. In common with Carnedd Llewellyn, there is a wind shelter and a large cairn. This is a good spot to stop for a break before tackling the steep rocky descent.
(3)The minor top of Foel Meirch is passed on the way down before passing along the Mynydd Du ridge. There is one section where there are boulders to clamber over before Mynydd Du. The easiest way of regaining the start is to join the path following the Afon Llafar. This leads out to a lane which can be followed back into Bethesda.