The Three Sisters Loop is one of the iconic backpacking routes in Oregon. It is a little over 40 miles long, and I took five days, taking the second day off backpacking to hike up on South Sister Peak. The first and last days were short days. The loop is amazing flat for a route that circumnavigates mountains, since such routes usually have to cross over ridges. My camping locations were: Green Lakes, Moraine Lakex2, Husband Lake, and a spot on the northeast side. I did this trip in mid-August. A lot of the route is in dry volcanic terrain.