From The Roundabout blog by the PG's Jon Schmitz, who "gratefully shared these before-and-after photos provided by Bob Genter of Mackin Engineering, one of many companies that had a hand in the trail development. The “before” shots are from 1997."
Above and below: Keystone Viaduct (Mile 30 on the GAP, which the Point Made! group crossed today)
To see more 'Then & Now photos" visit The Roundabout.