A combination of the Tees Railway walk and the Teesdale way provides a circular walk from Cotherstone to Romaldkirk.
The views from the railway walk are spectacular, with the path being flat, it gives lovely views up to the hills. Another interesting part, is crossing the high bridge over the River Balder - the signs warning horseriders to dismout are well advised (and it's not too good to peer over the edge if you've got a hangover either!)
The return route from Romaldkirk, along the riverside, also has some fantastic views. The river meanders as you walk along it, so there are lots of nice views down the river, and of the high cliffs on the northern banks.