A good start, or finish, is the caff in Craven Arms who are motorcycle friendly, they even give you a wipe towel and spray for your visor.
A nice stretch of road.
Start at the Shell garage/Tuffins cafe on A49 then take A489. There are a few sharp corners but mostly good,a long straight stretch into Churchstoke(another Tuffins garage/cafe) then superb piece of road to Newtown(watch speed thru Sarn and Kerry).
cyco