A good run, with an excellent gorge between nasty weirs. Watch out for Abercraf weir on a left-hand bend not far from the putin: it needs to be portaged early on river right. It can be inspecting by walking through the children's playground in the village. A great gorge follows before a double weir under a bridge just downstream of Ystradgynlais and the confluence with the Giedd. This can be difficult to stop above and so may be worth inspecting before you putin. A few easier weirs lead down the takeout on river right at the Twrch confluence.
Putin along a footpath on river left at the upstream A4067 bridge in Abercraf. Takeout on river right at the confluence with the Twrch (between Ystragynlais and Ystalyfera).
Rainchasers is best experienced as an app.