There are several ways to reach the cache, but I think these two are the most recommendable ones: You either start in Flattnitz at Restaurant Isopp (1 h, forrest hike, parking, optional: cable car - time-table) or at Hochrindl (2 h 45 min, scenic view) via Weißes Kreuz. If you intend to visit this place in winter, the petling might be covered by a layer of ice. If that is the case, add a log picture and you are good to go.
Edit 2020-08-12: Update listing text