From Munich take autobahn A95 towards Garmisch-Partenkirchen. Just past the tunnel at Farchant take the Garmisch exit. Stay on the main road through the center of Garmisch. This road turns into Zugspitz Str., which will take you to the Sheridan Kaserne and the Marshall Center. It will be on your left at a traffic light controlled intersection where Zugspitz Str. crosses Gernacker Str. Here is a map of the route.