I took the train and a bus to Laax. From there I started my bike tour. First it was Forest roads til Trin Mulin. After Digg the single trail started. Then in Tamins the ascend to Kunkelspass started. The road is up to 20% steep. The road after the Kunkelspass is asphaltic. But you can divert from time to time, so you could ride on dirt roads. After Magpraggsee it's only asphaltic road, but it isn't very busy. And from Pfäffers to Landquart, it's a nice road, with not much traffic... and you can go really fast. =^)