Take A470 to Builth Wells (the road runs alongside the river Wye). Pass through Llyswen, then Erwood. Approx 1/2 mile after Erwood, turn left at a staggered junction with 3 reflector posts on roadside next to a solitary house. The road is signed to 'Gwenddwr'. Go up the hill, over a cattle grid onto an area of common. After 1/2 mile, turn left at 'Y' junction at top of hill beside a stand of Scots pines. Fron Farm is approx 1/2 mile along this road, the first (& only) farm on the right before the village of Gwenddwr.
From the North & West:
At Builth Wells, take the A470 to Hay on Wye. After approx 5-6 miles, turn right at staggered junction with 3 reflector posts and follow as above.