I believe that the parish of Llanfor at one time was very big. It may have incorporated Llawr Bettws which has its own
Capel Glanrafon still. There is a chapel at Cefn Ddwysarn close to Llanfor. Again just up from there is a farm called Ciltalgarth which was once a small township. There is an old road behind Ciltalgarth with a tiny hamlet called tyn y bont where there are now just houses but earlier some of these buildings had been a chapel and a mill etc. There was a chapel at Rhydywernen. Also Capel Saron. Now some of these are nowadays classed as Llandderfel but as I said Llanfor was before Llandderfel a more important parish.
This is just what I have discovered from my own research in the area and perhaps someone else may not agree or know different but that is perhaps something for you to be looking at. If you phone Dolgellau the archives for merioneth in Dolgellau library they are the authority of course. Good luck with your research.
Regards Menai Dillon