The Idaho Northern branch is open all the way to Cascade. INPR/Rio Grande Pacific ran passenger trains from Smiths Ferry to Cascade last summer using the former WURR RDCs.
Payette River Flyer Website
The tunnel that was unstable was NOT the shortest solid rock tunnel near Smiths Ferry. The unstable tunnel was actualy a much longer one further south near Big Eddy. Work was done to stabilize it.