This starts/finishes at Fforest and takes about 90mins. From down by the Fforest lodge / Bwthyn pub you can walk down a path that leads to to the river it’s sign posted a bit but after walking straight for a 20mins you get to the Wildlife centre and you bare right towards the river, once you hit the river you bare right again so you start to go back on yourselves. You follow the river upstream. This is where starts to go up and it’s pretty steep at times at fairly strenuous.
It’s really great walk though, I’d recommend it.