You cross the Lapenscharte if you want to reach the Kasseler Hütte from the Greizer Hütte. The paths to the saddle and then from the saddle to the Kasseler Hütte …
The route from Lapenscharte to Greizer Hütte is very beautiful, more of a hiking trail almost to the gap. Only the last few meters of altitude are over gravel/boulders. On the other side, the route to the Kasseler Hütte is much more challenging.