We took the Monitor Ridge route from Climbers Bivouac to the summit. There were lots of people on the trail and camping at the trailhead. We managed to find a small, short spur road just before the last turn in the road and camped at the end of it. It was a great little site far enough away from others that we could crank up the music and make a lot of noise without bothering anybody. The trail/route was snow covered until a little beyond the timberline at around 5,000 ft. but safe enough for my grandma to do it. From there it was a rock scramble up the ridge ending in a steep ash slope 1,000 ft. from the summit. The ash slope is the most difficult; similar to hiking up sand. The only hazardous part of the climb was a small (200 ft. long) but steep snowfield near the timberline. There didn't appear to be any way around it. I tried glissading on the way down and slid uncontrollably into a pile of rocks, fortunately escaping injury. Be very careful on that slope! You can do the hike without any gear at all beyond a good pair of somewhat-waterproof hiking boots. With ice ax and crampons, however, the hike would likely be a really nice, easy trot up the snowfield to the West of the ridge. I had trekking poles which I would highly recommend for the way down, although no one else in my group had them and didn't have trouble. There was a well-worn glissade path on the West side of the ridge going from near the timberline to about 1,000 ft. from the summit.
The weather was absolutely as bad is it could be, with drizzle, constant thick fog, and near gale force from 6,500 ft. to the summit and back. Our only view was a brief section at around 6,500 ft. when we got an awesome panorama above a thick fluffy blanket of clouds broken only by Mt. Hood and Mt. Adams. From there, for a few moments, we could actually see a group of people standing on the summit. But alas when we got to the top the cloud cover had returned. One member of our group with a particularly active imagination claimed to be able to visualize the mind-numbing view of Mt. Rainier and the cascades. But the rest of us could only gaze into the abyss of white fog and wonder what the view would be like on a clear day.
We all had a great time though. Although I've done quite a few summit hikes in the Sierras, Mount St. Helens seemed ""bigger"" then the others; more like what you'd think climbing a mountain would be like if you've never done one. The fog, all the snow, and the volanic landscape made it easy to imagine that we were much higher than we really were. The rock scrambling and glissading made it challenging enough that I never got bored.