Getting to Culter Allers
From Biggar, head south on the A702 towards Coulter, as you approach the sharp turn in the village, turn south and take the unclassified road past the school for 3km to a junction by Culter Allers Farm. There is limited roadside parking for a few cars, alternatively there is verge parking 1km up the road, near the hill-route end.

Culter Fell
Leave your car and turn left up a private road. The road passes some forestry and sheep pens. A rough track heads uphill around some more forestry - take this for a bit, then look for a faint path aiming directly uphill through the heather. Follow this faint path which becomes more obvious further up. The path passes a few grouse butts and is followed over Fell Shin to Culter Fell's summit. There are fine views to be had from the trig point, particularly over to Tinto and towards the Pentlands.

Gathersnow Hill
A fence-line which crosses Culter Fell is followed south. The ground is slightly wet but very runnable down to Holm Nick. Upon reaching this col, ignore the track, cross the burn and head directly up to Gathersnow Hill's summit.

Return
Follow the fence westwards to a small heathery nick, from where the fence continues most of the way to Hillshaw Head. Return to the fence and lose some height. Although there's no path, navigation is straightforward as the fence-line is followed over Dod Hill and up to Hudderstone. On this summit, cross over the fence to the west side and then on a path, start descending Hudderstone. The path joins a track, which is followed over Cowgill Rig, past some forestry down to the road 1km south-west of route start.