Thanks for the pictures, Alex. Must be mild weather if you're at the summit with no hat and wearing a t-shirt. Lots of tracks in that third picture - are any of them Roman roads?
The straight track running across into the trees on the left is a historic cattle drovers road, though nowadays it is mainly used for logging lorries accessing the modern forestry plantations. A herd of black cows can however just be spotted along the track near the centre of the pic.
The darker tracks are probably the remains of early twentieth century army trenches. The army trained here from 1903 till 1959. The vegetation grows more lush because the trenches accumulate water.
No Roman roads here that I know of - the road which follows Hadrian's Wall is a few miles further south, and the road north from there to Trimontium (near Melrose) is a few miles to the east of here.