Pleasant touring paddle. The harder 2+ rapid is near the end as you enter Builth Wells. Takeout shortly after joining the Wye.
Putin at the B4519 bridge (just off the A483) near Garth, or if you want to make the run 4km longer use the bridge in Llangammarch Wells. Takeout from the Wye in the carpark next to the river in Builth Wells.
Rainchasers is best experienced as an app.