In reply to Fex Wazner: We did it in one fell swoop; parked car in carnedd car park, camp at the old mines at the bottom of craig yr ysfa one night, take a bottle of gin and a few reefers and a large stereo, preferably rammstein (oh the irony).
The first one; follow the river from the ruins along the scree and keep your eyes peeled; easy to miss even though it is large stuff. Once you got it, carry on following the river uphill, not the path. There is actually a fair amount of stuff from the top wreck washed down the river.
Once a fynnon, you'd have to be blind to miss it. Shit everywhere. Then, its a yomp to the ridge, taking in the foel grach shelter then scooting off down right, not such an obvious sight, clear day might help.
Then, back to the ridge, go to the foel fras ruin, then straight down the hill back to the carnedd car park.
there is also another site at SH 726 635