A useful little route to avoid part of the main B320 between Schladming and Radstadt, especially if doing Obertauern.
At Gleiming on the B320 take the turning for the Reiteralm Prunegjet Ski Lift and for Forstau. Follow this road all the way to Radstadt. Initially it winds along following the river through the trees, gently climbing to the village Ski resort of Forstau. Then on up to the top with some nice sweeping bends to keep you amused. It then takes a fairly straight route descending slightly before some nice bends on the drop down to Radstadt.
I use this route a lot when going to Radstadt because it avoids numerous speed restrictions, heavy traffic and Police presence on the main road and is far more enjoyable.