The first time I attempted this hike the weather was very much against me. Lots of fog concealed the path as well as the lookout, and dew covered every portion of every plant, soaking me shoes and pants. The second time I made sure to time it better and the results were fantastic. Your reward at the top is a fire lookout with Mt Rainier in your front yard.
Kelly Butte is accessed from Hwy 410 heading towards Mt Rainier. The forest road to get there is tricky, poorly signed, long and rough. If you are able to find the trailhead, you then need to make sure to take the new (2007) trail up the hill rather than the old scramble "trail" up the rock face. In the fog, I missed the normally obvious new trail and ended up making the hike much more difficult and dangerous than it needed to be.
Once at the top of the ridge the trail opens into a large meadow filled with Bear Grass and flowers that seems to surpass the distance of the hike. It was here that I convinced myself I had taken a wrong turn the first time there so I turned around only about 1/4 mile from the lookout. There would have been no view anyway, so I don't think I missed much. Returning in the sun a month later showed me just how much I did miss.
Camping is allowed in the meadow and makes a perfect scouting or family outing because the (new) trail isn't too long or difficult. It's also possible to sign up as a volunteer to man the recently repaired lookout itself if you want to stay there. Ask the forest rangers at the Enumclaw Forest Station for details.
Map & Stats
3.5 mile out & back
950 ft elev gain
5409 ft highest elevation
Northwest Forest Pass required