someone posted this route in fodors.: "Garmisch- to Zirl.
At Zirl, get on the A-12 autobahn past Innsbruck and north- east to the Oberaudorf exit. From there, head on a lovely road east past the Wilde Kaiser Mountain massif to Koessen, Reit im Winkel. Reit is perhaps the prettiest mountain village in Germany.
In Reit, pick up the B-305 Deutsche Alpenstrasse (German Alpine Road) to Berchtesgaden". we are trying to find out how long (in time) this trip will take (assuming no scenery stops)