Charlotte Guest* gives the following account of being too lazy to get herself up the hill...
...if we are surprised to find this singular hunt thus recorded, and even the name of Arthur's dog Cavall preserved in connection with it, much more may we be astonished to learn that Carn Cavall is no fabulous mound, the creation of the poet or romancer's fancy, but is actually a mountain in the district of Builth, to the south of Rhayader Gwy, and within sight of that town. Such was the interest excited in my mind by the discovery of the existence of such a remarkable piece of evidence, corroborative of the great antiquity of the traditions contained in the Mabinogi of Kilhwch, that I prevailed upon a gentleman to undertake a pilgrimage for me to the summit of Cefn Carn Cavall. The following is the account he wrote me of his expedition; whether he has succeeded in finding the stone itself, bearing the imprint of Cavall's footstep, I must leave to others to determine.