In reply to Ridge:
If you don't mind a drive, a scenic one, you can do Ettrick Pen, Wind Fell & Loch Fell and return by Southern Upland Way to car.
Also across from Grey Mares Tail the ridge from Herman Law to Bodesbeck Law covers 4 Donalds. Better if there is a car either end, if not return by ridge descending back to car just before Herman Law.
Great views and you will not meet many other walkers, if any.