Extending Elztalbahn to Hausach?

How would this geography map to my layout? Let's follow a train from Hausach to Freiburg.

Hausach is represented by hidden staging. Train takes the right track on the ramp, passes the tower and the creek bridge (which would be crossing the river Elz) and arrives in Oberprechtal (or Unterprechtal), formerly known as Talheim. As we continue south, the train is passing through Elzach (not modeled, represented by the fairly long tunnel along the wall), and arrive in Gutach (formerly known as Emsingen), which is also the overnight point for commuter trains from/to Freiburg. We pass over a stone viaduct, and downgrade over the large S curve until we're down at the tower and take the ramp down into hidden staging which represents Freiburg.

Now, ... this is really doing things backwards, one should find their situation to model, then build it, not the other way around. Also, Gutach and Elzach are down stream from Oberprechtal, so it doesn't make sense to have a grade going up the hill. Further, the actual Elztalbahn track is running at the bottom of the valley, so having a viaduct doesn't make sense. Maybe I'll find myself a Black Forest valley that doesn't have an actual rail-line to compare against ...