Clearcuts hidden by snow make the approach more scenic, thus the winter recommendation.
About 40 mi east of Everett, take road 62 and 6220. Be sure to take the left fork and keep heading uphill. At a flat spot with lots of logging remains is a swampy puddle in the road where I stop. Some people keep driving to the trailhead. Take the next left about a mile past the puddle at a switchback and look for the trail on the right near the end of the road. It isn't easy to see, and it starts out very steep.
The trail follows the ridge line, often at the edge of a recent clearcut. Recent work on the trail has left it in remarkably good shape. The route heads roughly south above the eastern cliffs of the mountain. There are a few avalanche slopes, so pay attention. Exposure is minimal, however, and avalanche danger is low on much of the route. Views at the top of Index and a 360 degree view of the Olympics, Rainier, Baker, and billions of peaks.
Follow the climbing route.