Day 1: Phelps Cr TH - Lyman Lake via Spider Gap ~ 12 miles
3:30 wake up in Longview, 5 or so hour drive to the Phelps Cr TH, on the trail by 9:30 am. Road to Trinity is fairly good til the last 2 miles, road from Trinity to Phelps Cr is less good but still passable with a regular car. You can do the road walk either at the beginning or end of your hike. If at all possible, do it first. I did it last, and it is not fun!
Phelps Cr Trail is gorgeous, lightly traveled, excellent tread, tons of water available, no bugs, no snow. Beautiful big trees, peekaboo views through the forest of nearby peaks.
When you hit Spider Meadow you start getting views of surrounding peaks. About midway through the meadow there is a big pile of avalanche snow. I got turned around here, thinking I had already passed Phelps Creek and started looking for the trail to Spider Gap. Don't make my mistake, I wasted maybe an hour of time on the snow, in avalanche fall, bushwacking, etc, which took a physical and mental toll later. For whatever reason I thought there was no official trail from Spider Meadow up to Spider Gap, but that is not true. Just stay on the main trail, eventually you'll hit a signed trail junction at the bottom of the headwall, and you'll turn up slope toward the Gap.
The ascent from the meadow to the Spider Snowfield is steep and hot. Bring lots of water. The snowfield is soft and safe on a warm day like the one I did. Don't need any special equipment but poles might make it easier. It's apparently only a mile but it feels longer.
Spider Gap is spectacular, views for miles, and a good place for lunch. You'll have to swat a few deerflies, though, precursor of things to come.
Heading down now onto the Lyman Glacier is definitely steeper. With warm, soft snow a set of poles is all you'll need, but an axe or maybe crampons would make me feel safer. There's a thread at NWHikers.net with excellent info about how to find your way down the snow and onto a trail. Don't go right too soon are you end up cliffed at an overlook. But don't go right too late (like I did) or you miss the main trail and end up having to scramble down scree for hundreds of feet, which is tiring.
Once you find the trail, it's an easy up and down to Lyman Lake, which is beautiful. Camping sites are pretty mosquito-ey, but right at the lake there were hardly any flies or skeeters and it's got lots of warm, shallow areas perfect for a hot day. Gorgeous views!
There were some camping spots up higher on the ridge between upper and lower Lyman Lakes, which were scenic, breezy, and lonely, but you would have had to have gotten your water from upper Lyman lake or earlier, as there is no water right at those sites. Worth it though, for those who plan ahead.
Day 2: Lyman Lake - Cloudy Pass - Image Lake - Miner's Creek ~ 13 mi
On trail about 8 am. Easy jaunt up to Cloudy Pass with great views but again, lots of bugs. Definitely bring a headnet and spray. I was going to go with just a tarp since we had such great weather, but in the end I brought my 16 oz homemade bug tent too, which I was very grateful for - more for flies than mosquitoes.
The hiker shortcut to Suiattle Pass is snow-free, no trouble, but kind of steep and rocky.
Trail to Image Lake has a few blowdowns, nothing big. There are signs of active bears en route to Image Lake with several stripped trees and tons of scat near the miner's cabin ruins.
Image Lake itself was infested with horseflies. The campsites appear to be located over a ridge from the lake itself with great views of Glacier Peak but none of the Lake. I didn't camp here, instead moving on to Miner's Creek.
Hint: Miner's Creek bridge goes right over a 4 or 5 foot deep pool of water in the creek, exactly right for jumping in to neck depth for a great rinse off and cool off on a hot and dusty day. Water is cold but tolerable.
There aren't a lot of good campsites at Miner's Creek - I only saw one good one. I made do with a so-so spot and I didn't see any others sites.
Day 3: Miner's Creek - Middle Ridge/Sheep Driveway - Buck Creek Pass - High Pass Lookout ~ 12 mi
On the trail at 8 am. From Miner's Creek you're up to Middle Ridge through forest then parkland, again lots of flies and mosquitoes. There is an unmaintained but well-known trail there that you can go up about a mile and get big views of Glacier Peak et al. Worth it. Then down to Small Creek, a beautiful stream, then back up to Buck Creek Pass. This is around 6 mi, pretty easy, I was there before 11 am.
Note the official Buck Creek Pass campsites are down a hundred or two hundred feet in elevation next to a little stream. They have better access to toilets and water, but much inferior views, also cooler at night and less breezy, bad for bugs. Try to get the unofficial site visible from the main trail if you can, the one you pass as you first head down toward the official camping area.
After setting up camp at the unofficial campsite just off the main trail - the one still high enough to see sunset and sunrise on Glacier Peak - I set off for a dayhike to the unnamed pass just short of High Pass, described in Doug Lorain's "Backpacking Washington." It's an easy first couple miles, rounding Liberty Cap with ever-better views of Glacier Peak, etc. After a long 2 miles you hit an unnamed saddle and round the north-facing side of a ridge. Then you start to hit snowfields - about half a dozen in all. The first is too steep to safely pass. You have to scramble briefly down and around, which isn't too bad. The next few are safe to pass, with proper precautions. To be safest you should have an ax. I didn't. I had in-step crampons, but it was warm and the snow was soft. In retrospect I was probably taking a risk. The final snowfield which is literally immediately before the final destination is not passable. However you can scramble sort of back and up and reach the ridgeline, which you can then traverse briefly to the pass for the best views. Whoa!!! Icy Triad Lake, mostly frozen over, tons of snow and ice, glaciers, peaks, Glacier peak visible to the right, etc. This is an awesome and worthwhile short day hike if you can do it safely! Thunderheads were starting to build at 1:30 so I headed quickly back, just in time to cover my bug tent with my tarp as the first (and last) raindrops fell. Note there is no water once you start up Liberty Cap, bring what you need from Buck Creek Pass.
Day 4 - Buck Creek Pass - Trinity - Phelps Cr ~ 12 mi (plus 1 mi in a vehicle)
7:30 am start. Long, long, steady downhill with spectacular views of Buck Creek Valley and many snowy, icy peaks and slopes. The undulating portion of the valley can be wet with dew, swarming with flies, and hot and humid as there are a few avalanche slopes that are exposed. There are some ripe huckleberries here, but the flies keep you from hanging around too much. Saw some inbound hunters on the way down.
Once you get to the road, it's a long 3 miles, maybe 3.25 miles from Trinity parking lot to Phelps Creek TH. As mentioned, try to do the road walk on entry rather than exit. I found this a very painful and not fun part of the hike, would have been better at the beginning. However, you probably need 5 days to do it that way (staying the first night in Spider Meadow after a 10 mile hike in including the road walk), otherwise you end up starting off with a 15 mile plus day, and the last 3-4 miles are descending the Lyman Glacier in late afternoon while you're probably pretty bushed, which doesn't sound that safe to me.
Great hike, would be nicer in 5 days than 4 but rarely is the hiking steep and the trails are all well-graded and easy to travel (obviously excepting the Spider snowfield and Lyman Glacier).
Really spectacular scenery. Maybe flies and skeeters will be doing out shortly with cooler weather coming this week. Huckleberries just coming on. One of the most scenic backpacks I've done! I didn't mention all the flowers, just tons of lupine and many other common Cascade flowers on the parks of Buck Creek Pass, Lady Pass, Cloudy Pass, etc.
Thanks to posters at NWHikers.net for their tips on traversing the snowfields at Spider Gap!