I know you posted this a long time ago, but if I rememeber, Sawtooth is a fall race. I have spent much time running on the SHT, and it is very rugged. The rocks are quite sharp and there are a lot of them. It is rather narrow, rocky, and holey single track. There are areas where you climb up steep, sharp rock falls and boulder beaches. I do not run most trail barefoot, so I can't tell you whether you should or not. But it's pretty rugged. This is part of the trail, for example.