The key is, as you approach Upper Boy Scout Lake, you go left (south) around a ridge so that as you approach Iceberg Lake you have Pinnacle Ridge on your left and this ridge on your right. But you will find a use trail the whole way. When you get close to Iceberg Lake, you can choose to stay on sand and approach it from the south, or climb the lake's headwall (a little class 3) and approach from the southeast.
You'll find a picture if you Google "Clyde Meadow Mountaineer's Route."
