Walking in the Welsh Countryside

Im thinking of heading up to Brecon Beacons for a spot of autumn/winter walking. Does anyone have any suggestions on which parts are good to go to. Also, Ive heard there are some hidden gems in the beacons, does anyone have any inside knowledge on where these sights might be?

I don't know how many of us here would be familiar with the area, but there are a lot of folks at DPS from that a side of the pond.

Thanks Jim. What is DPS?

DPS = Digital Photography School.