As Bay says, over old bridge, turn left by Mitsubishi (used to be Suzuki) garage before racecourse roundabout, twisty fun to Usk and on to Aber, A40 through to Brecon then Llandovery (brekkie at West End cafe), loop back up through Builth Wells, through Talgarth and back onto A40 into Aber.
Obtain chisel to wipe grin off face......:thumbup