Parking is in a decent car park underneath Fan Gyhirych, but bear in mind that this route ends at Carreg Cadno because I wild camped for the night and returned back to the car via a different route the next day.
The route takes you briefly along the main road – you can walk safely on the grassy verge – before you turn up a smaller single track road. You then turn onto a gravel road that takes you up into the mountains.
We walked to Fan Nedd and Fan Gyhirych first, before picking up this gravel road again and following it down towards Carreg Cadno. To get to Carreg Cadno you do need to cross a couple of barbed-wire fences, there are a couple of spots where it is fairly low so you can step over it with a bit of care.
The summit is very rocky and gives you good views in every direction, including down to the sea. A nice hill, we wild camped in a sheltered spot of which there seemed to be a few as the hilltop is craggy and has lots of lumps and bumps.
A good hill, in can be walked from a few directions and the Beacons Way trail crosses not far below the summit.