No special access issues
Leave the A5 at the southern end of Bethesda, heading up the road signed Braichmelyn. Continue past the houses until you reach the bridge. Turn left and park at the top of the housing estate.
Walk back across the bridge and back down the road you've just driven up. Take the first road on your left (Nant Graen) and continue to the end of the road. Walk in front of the houses and respectfully along the footpath that cuts through the owners garden. Please keep to the path and keep noise to a minimum.
The Afon Caseg Gorge will appear to the left hand side before you meet up with the riverside. Past this and on the riverbank is the Happy Slappy block or to reach Electrohpiliac, Oh So Thin and, most importantly, the Super Boulder, head into the woods from the Gorge away from the river on a vague path. Eventually you will reach a clearing and the obvious Super Boulder behind your left shoulder.
Sadly, to find The Prow, Braichmelyn Bach, Braichmelyn Block and the Hidden Block, you will need to participate in a bit of bushwacking. The vague path network follows from climber's right of the Super Boulder, across a dry stone wall and turning right. Navigation is difficult at best and accurate GPS locations have been given on the map here. Alternatively, approach descriptions can be found in the North Wales Bouldering guide from Ground Up.