Easy to do. Folks do it in one day all the time. The sitkum route is a cakewalk, so it can be done quickly. Others may take more time depending on fitness and experience of the climbers involved.
I'll be on the N. Cascades hwy until the 16th of Sep and wanted to get out to the spires for a day. Not looking to scare myself or anyone else, so the trade routes are fine with me. PM if you are interested.