Enter Mt. Rainier National Park at the Nisqually entrance, which is the one at the southwest corner of the park that everybody uses to go to Longmire and Paradise. After you've visited Longmire to confirm your campsite reservations and register your climb, you drive back almost all the way to the Nisqually entrance and look for the Westside Road on your right. Turn onto it and go all the way to the end of it, where you find a small parking lot. Years ago, you could drive the road all the way to the Round Pass trailhead. Now Fish Creek cuts across a section of the road, so you have to walk from the parking lot up the road for a few miles to the Round Pass trailhead. When you reach the Round Pass trailhead (ele. 3900 ft.) you may want to stop and spend a few minutes at a small memorial site nearby. It honors a group of soldiers who died when their transport crashed on Rainier a few decades ago.
From the Round Pass trailhead, the path goes into the woods, descending for several hundred yards then turning uphill again. The Puyallup River eventually will appear on your left. About a mile or so from the road, keep your eyes open to your right and look for the interesting rock formations on the hanging cliffs of the Emerald Ridge. And about 1.5 miles from the trailhead, you reach the South Puyallup River Camp and the intersection of the Wonderland Trail. (We spent our first night at this camp, which has tent platforms, ample running water and an outdoor toilet. If you plan to do likewise, make your reservations early, because this is a popular campsite.)
Once you reach the Wonderland Trail, you've got a choice. You can head North (left) on the Wonderland, up a series of switchbacks toward St. Andrews Lake and the Puyallup Glacier. Or you can head East (right) on the Wonderland to the toe of the Tahoma Glacier. The latter route is shorter, but the crevasses on the lower Tahoma Glacier may be difficult to navigate. In late June, we found the route passable on our descent. But it may not go in mid-July or later.
For our ascent, we chose to go north on the Wonderland. The trail climbs up through a series of switchbacks to the top of a wide ridge. Once you hit the ridge, you turn east and walk along its broad spine for several hundred yards. The ridge is snow-covered until early July. Way up high and to your left, you see tthe bulk of Rainier and the Tahoma Glacier spilling down. In front of you and much closer, you're looking up at the lowest reaches of the Puyallup Cleaver, which is the ridge between the Puyallup Glacier and Tahoma Glacier. But keep your eye out to your left for the Wonderland Trail to break left and head towards St. Andrews park. If you didn't spend your first night at the South Puyallup River Camp, then consider ending your first day at St. Andrews, which is a nice place to spend a night. From St. Andrews, you'll break off from the Wonderland trail and head uphill steeply to get on the Puyallup Cleaver.
We weren't interested in spending a night at St. Andrews, so instead of turning left and following the Wonderland Trail to St. Andrews park, we opted to keep walking east/northeast up some steep ground to the spine of the Puyallup Cleaver.
Once we got onto the Puyallup Cleaver, our goal was to get as high on the Cleaver as possible for out high camp. We'd been on this route in 2002 and knew of a good spot for camping on the Cleaver at around 9,600 feet. We chose to hike mostly on the right (south) side of the ridge until we got to Tokaloo Spire (ele. 7684 ft). Above that spire, we crossed a saddle to the left (north) side of the cleaver and dropped to the Puyallup Glacier for the slog up to our high camp on the Cleaver. As we worked our way up the Puyallup Glacier, we edged farther and farther to the right (south) until we were nearly back on the spine of the Puyallup Cleaver once again.
We got back on the Cleaver at around 9,600 feet, just below St. Andrews rock. From that spot, the route plunges over the sice of the Cleaver onto a steep snow ramp leading down to the Tahoma Glacier. We chose to camp on snow platform at the very top of this ramp. There were a few bivy sites on the rocks nearby. We took a rest day at this spot.
Some teams doing this route prefer to go up over St. Andrews Rock and descend to the Tahoma Glacier from there. Late in the season, when the Tahoma is really broken up, this may be the only route that will go. But we made up our minds to descend the ramp at 9,600 down to the Tahoma, which didn't look all that broken up.
Crevasses are the major issue on the the Tahoma, even in June. For the first two or three hours, I think we climbed dead center up the Glacier, though we somewhat to the left in the early going. Progress may be slow on the lower section of the Glacier, which is not as steep but tends to be more broken up. You will encounter some difficult ground below 12,000 feet. There are icefalls and a few difficult traverses around these. Above 12,000 feet, the glacier is less broken up and you can get into a rhythm, but the ground is steeper. We reached the crater rim a little before 9 a.m., shed our crampons, and walked across the summit plateau to Columbia Crest.
If the Tahoma is badly broken up, you may find your way up via a chute on the far left side called "The Sickle." We descended the Sickle. We saw signs of avalanche and icefall hazard. Stay off it later in the day.
The quickest way back to the car from the 9,600-foot camp is to retrace the ascent route I've described. But another option is to descend onto the Tahoma Glacier once you get to the saddle above Tokaloo Spire. As you're descending the Tahoma, look out to the left (southern) flank of the Glacier to a delta of grassy/snowy ground above a steep moraine slope. That's where you'll pick up the Wonderland Trail, eventually. Work your way down the right (north) side of the Tahoma Glacier. The last section of the Tahoma is a little tricky because there's a cliffband at around 5,800 feet with waterfalls going over it. When you reach it, you'll need to go to the far right (north) to find the ramp around the rocky dropoffs. Then pick your way across the Tahoma's lowest reaches and scoot up the moraine slope to the grassy/snowy delta where you'll pick up the Wonderland Trail. Head right on the Wonderland, which takes you back to the South Puyallup River Camp.
Crampons, ice axe, harness and rope. Pickets and or Ice screws for running protection or, if you decide to climb this late in the season, rappeling into and ice-climbing out of crevasses. An altimeter is almost a must.
Give yourself five or six days for this climb. This is a climb for people with a fair amount of mountaineering experience who feel they're ready to get off the well-traveled routes on Rainier and tackle a long and lonely route with some real navigational and technical challenges. Have your crevasse-rescue technique nailed. Be prepared to cover some steep ground.