I lived in Wales as a kid & don't have any trouble with names like Ochrwyth or Llanfairynghornwy - they really are phonetic, once you know what the phonemes are. (Although admittedly the letter Y behaves unpredictably.) What always got me and still does is my father's birthplace, Rhosllanerchrugog - I never know quite what to do with the 'Rh', and once I've got over that hurdle I have to make sure I remember the north-Walian 'u' (in south Wales you'd just pronounce the last bit 'reegog', but Rhos isn't in south Wales).

In short, it's a lot easier than it looks, but that doesn't mean it's easy.