Running is one of the local activities enjoyed by your webmaster (when not injured). The new Coed-y-Brenin Visitor centre has two dedicated trail runs. Fell races also take place in this area such as the Rhinog, Moelfre, Y Llethr and Rhobell Fawr races which attract competitors both local and international. There are also training runs from various start points including the Coed-y-Brenin visitor centre. Your webmaster organises the Tyn-y-Groes Hill Race which takes place on the last or penultimate Saturday of June each year. It is rerun in a more lighthearted fashion on Boxing Day each year starting and finishing at the local pub. Runners are perfectly free to train and run almost anywhere within the Coed-y-Brenin and on the mountains. There are also road races such as the Dolgellau 5 and trail races such as the Penmaenpool 10. Details of all races can be found at these sites
I am happy to give advice on request and if you need a guide I'll take runners training on local paths, tracks and mountains providing you can keep your speed down to my level (thats about 130mins for the Cader Idris or Snowdon races).