Rhinog Fawr by the Roman Steps

Rhinog Fawr rises to 720m in the Rhinogydd, the third-highest summit of the range, and Wikipedia describes the hard sedimentary rock under its heather as making progress on foot difficult. The Roman Steps, the usual way in, are not Roman. AA RatedTrips calls them part of a medieval packhorse track, used by drovers taking cattle from Harlech towards the markets of England, and notes that the Romans, who had a fort near Trawsfynydd, might have used a predecessor.

Walking Britain starts at the Cwm Bychan car park, which RatedTrips lists as an honesty-box car park at the head of Llyn Cwm Bychan, reached by a minor road from Llanbedr. The Roman Steps climb through woodland into rocky ground, with a flagged path to the col at Bwlch Tyddiad. Beyond it the route leaves the path for a narrower one through knee-deep heather to Llyn Du, then climbs a gully where hands are needed on a short section, onto a summit plateau marked by a large cairn. The guide calls the descent to Gloyw Lyn hard to describe, warns that the terrain is confusing, asks walkers to carry a large-scale map and compass, and does not recommend the walk to inexperienced walkers. Barmouth is the nearest base on this site, around 16km away in a straight line.

On Ordnance Survey Explorer OL18, the sheet Walking Britain lists, the circuit measures 8.1km with 585m of ascent, around four hours ten minutes, graded mod/hard. It suits a walker who can navigate across heather and boulders. Anyone relying on a waymarked path should not start, because the guide itself calls the ground beyond the col confusing. For mountain cliffs without any navigation, Cregennan Lakes sit on the lower slopes of Cadair Idris and are reached by car.