Having walked up Carn Gafallt, one can easily see why Charlotte Guest got someone to struggle up there for her. The height gain itself is not a problem - the road that runs from the Elan visitors centre to Llanwrthwl will carry you most of the way up the mountain and there is a little room to park by the roadside near the first houses you come upon. However, from there to the top of the hill is pretty unpleasant. The main reason for this is the knee-high covering of gorse, which swathes the mountain in a manner that almost makes you wonder if someone is trying to stop you reaching it. The best way to the top of the mountain isn't to head directly up - instead follow the forestry track, which will both circumvent the worst of the gorse and take you closer to the cairns. If you want to you can then head from the cairns through the gorse to the plateau. This is well worth the extra effort - the view from top of the mountain is undoubtably a Wonder of Britain all on its own.
The plateau at the very top is littered with smaller rock-piles (Photo), though easily the most impressively man-made looking feature on the way to the top, a large mound (Photo), is infact the end of a buried rock-ridge (or possibly a moraine with large rocks in it). From the top of the mountain you get a good view of the grey rock cairns (Photo), which sit at the end of a broad but sharply-defined col which was probably carved by a small glacier spilling out over the edge of mountain from one of the valleys on either side during the last Ice Age (> 18000 years ago).
The cairns are some seven to ten metres across and a couple of metres high (Photo), irregularly shaped, and dug into at the centre and edges, either by treasure-hunters and/or to make sheep-hollows. Although there is no particular sign of the Guest rock (it seems highly likely the "gentleman" picked the first he could after struggling up there) there are a broad selection of hollows on many of the stones which, as the gorse-induced endorphins course through your veins, can look a little doggish. Here are a few: Rough; Ruffer; Ruffly right1.