In low-snow conditions, most of the east ridge route to Pfeiferhorn is class 1 and 2. The possible exception is this "causeway" (highlighted in purple) just east of the summit cone; it is composed of jagged boulders, and unless you are careful, you may find yourself crossing some sloped sketchy ledges. The remaining route up the summit cone actually has a loose class 2 trail of sorts.
(No, the rocks aren't really purple; I altered the color to make them stand out.)
This informational picture is mean to be used with this
map.