The Mynydd March stone, along with it's neighbours Buwch a'r Llo, has the easiest access of any standing stone in north Ceredigion. It's right next to the road, and there's no boundary fence.
The stone has two distinctive cracks running diagonal across it, presumably caused by weathering. From some angles it looks very strange, like some sort of a half peeled megalithic fruit. Of the three stones on the verge of the road, Mynydd March is the smallest and the easiest to miss as you drive past.
These stones are on one of my routes home, so I see them regularly. They are the best known and most easily accessible of a large number of Bronze Age standing stones in the area.
The Buwch a'r Llo (or cow and calf) stones are on the east side of the cattle grid and the Mynydd March stone is on the west side. All three stones are on the southern side of the road (i.e. on your right coming from Penrhyn Coch), and they are right next to the road.
Watch out for idiots driving scrambler motorbikes and 4x4s in this area. It feels relatively safe walking on the road, but the 'off-road' fraternity don't tend to have their brains engaged when they drive along here.