As Ian says Builth to Llandovery gentle roll up sugar loaf stop at the picnic site just before top spectacular view. Then A40 to Llanwrda nice cafe there too and up to Lampeter. I ride all 3 roads regularly and they are indeed quiet.The easiest way is via Llandovery on the A roads. Not terribly busy and reasonably flat. West End cafe in Llandovery is a good cyclists' stop.