Jīnshānlǐng Great Wall, near the town of Gǔběikǒu, is the most remote part of the wall to reach from Běijīng. That means fewer people to interrupt your hike along a steep section of the wall that winds through some stunning mountainous terrain. Note that the watchtowers are in various states of preservation and some have been stripped of their bricks.
Hiking (in either direction) on the restored section of the Wall here is straightforward. There's an east gate and a west gate (about 7km apart), although the east gate was closed at the time of writing which means you will have to retrace your steps. From the west gate, turn left to head towards the east gate. If you need it, there’s a cable car by the west-gate ticket office. If you want to find some unrestored sections, turn right when you hit the Wall and just keep going. This stretch eventually leads to Gǔběikǒu (6½ hours), although you have to leave the Wall for an hour or two in order to walk around the boundary of a small military camp.