Y Llew Coch (The Red Lion) in Dinas Mawddwy Is a very fine watering hole. Speaking to the landlady last time I was in, she said that times had been hard, but now they get lots of trade from the strange folk that Photograph the planes on the Mach Loop.
I think the Star may still offer B&B. Whilst running in the local hills recently I bumped into a walker on the Cambrian way who said he had stayed there.