Park at or near the aptly named Rock farm,follow the path east up between the cliff's.Upon reaching level ground look for the fence off to the right follow it to the south and you'll come to the big barrow with great views and the rocking stone, of course I didn't know it would rock till I stood on it, boy was that wierd.(from here you can see Castle Dinas Bran)
Follow the fence back north for the standing stone and cairn,after reading Treaclechops field notes I doubt she actually got the right stone this one is about 5ft tall stuck in a fence right next to a big cairn,although there are smaller stones at it's foot but these probably came from an old field boundary as they follow the line of the fence.
A good stone in a fantastic place, go now
This is a short lump of greyish limestone that points up from the ground at a jaunty angle, probably no more that 2.5-3ft high. Stumpy and solid, it is the smoothest, roundest piece of rock for miles around; everything else is stepped and fissured limestone. It does appear that a few pieces have split or broken away over time, and so it might have stood considerably taller originally. It has the characteristic hollow in the ground on one side where the sheep use it as a leaning/scratching post; and as ever, the views it commands are stupendous.
Fair enough, this might not refer to this particular rock. In fact it's true to say that it probably refers to some random rock on the steep slope of the Creigiau Eglwyseg (Eglwyseg Rocks) below. But it shows you what the rocks are like round here.
Thomas Morris happened to be returning home from Llangollen very late on one Saturday night in the middle of the summer, and by the time he reached near home the day had dawned, when he saw a number of the Tylwyth Teg with a dog walking about hither and thither on the declivity of the Eglwyseg Rocks, which hung threateningly overhead. When he had looked at them for some minutes, he directed his steps towards them; but as they saw him approaching they hid themselves, as he thought, behind a large stone. On reaching the spot, he found under the stone a hole by which they had made their way into their subterranean home.
Maybe midsummer had something to do with the sighting.
From 'Celtic Folklore, Welsh and Manx' by John Rhys (1901).