I walked from Narukoonsen station along Route 47 to the Kokeshi (wooden doll) museum. From there I continued up the road (bypassing the highway tunnel which is not pedestrian-accessible), rejoining Route 47 not far from the amazing viewpoint at the resthouse over Naruko Gorge. Finally, as the sun set, I made my way to Nakayamadairaonsen station, and from there back home!
Unfortunately, the hiking trail that normally runs along/inside the gorge is currently closed (2013) due to damage sustained in the 2011 earthquake, but the view from the resthouse and shorter Ofukazawa Walking Trail is still amazing.