Is this the route we took some of the way back from the Welsh meet?
https://maps.google.co.uk/maps?saddr=Welshpool&daddr=newtown+to:kington+to:hereford&hl=en&ll=52.251346,-3.110504&spn=0.718818,2.113495&sll=52.35799,-3.032227&sspn=0.717089,2.113495&geocode=FXyIIwMdWf3P_ymtZ4H3SlVlSDGEobNYPaFpfA%3BFXBFIQMdLnLN_ykJF6EZuOJvSDGuTItPjY8Vjw%3BFd6QHAMdyMfR_ym3lHkzhNdvSDFdzYK7TfNI0w%3BFU5RGgMduo7W_ylBU26qJdRvSDGWbDz9S5qc1Q&mra=ls&t=m&z=10
Also looking at that map i'm sure if you turn west at Llandrindon Wells and head out towards Aberystwyth that A470/A44 road is pretty fun.