On the Marine/S.A.S side, go into the barn for a defensive sniping location. In one corner are some pallets (wooden boards) that you can climb to reach a ledge that goes around the barn. There are many gaps in the wall that you can snipe from. Note: Helicopters can see you.
At the bottom of the hill, go across the creek and find a rock with grass on it sheltered by two boulders. Wear a Ghilly suit and snipe from there to have a view of the entire cliff ledge.