TL;DR:
Creek crossing on FS Road 4330 - not all vehicles could pass (picture)
Snow fields from Squaw Lake to Cathedral Rock - water running beneath the snow, unsure footing (picture)
Downed trees across trail - pass easy with care (picture)
Trail creek crossings - pass easy with care
Trekking poles and boots were helpful
If its sunny out, take sunscreen, the snow reflection will get ya
The full story:
Drove out of Seattle Friday after work and made it to a camp site near Fish Lake on FS road 4330 (the road that Cathedral Rock trail head is on) around 8pm. The road has a creek without a bridge you must ford that might be difficult in vehicles without much clearance (see picture). The rest of the road was not much of an issue. It had lots of potholes/ruts as most dirt roads, but with a little care most any vehicle could make the drive. Make sure to slow down through the private property areas.
I hit the Cathedral Rock trail, #1345, at 8:15am the following morning. The trail switchbacks through the trees for a little over two miles to Squaw Lake. This portion of the trail had many trees down across the trail that required you to duck, hop over, or go off-trail around them. There was also intermittent snow and a lot of melt water running down the trail due to the mid 80's weather. There was also a stream or two that required crossing, you can find easier routes over if you walk up or down them a ways. Roughly a half-mile before you reach Squaw Lake, Trail Creek Trail # 1322 breaks off to your left and heads down to trail #1310 and Waptus Lake. Squaw Lake itself was mostly absent of ice and a nice stop for a quick snack.
From Squaw Lake, I tried my best to follow the trail around to the north west side of the lake, where my map showed the trail heading up towards Cathedral Rock. I couldn't really locate where the trail diverged from the Lake and ended up just following a boot path in the snow hoping those before me knew the way. The snow is patchy at this point so I soon lost the boot path and just hacked my way through the woods in the general direction of Cathedral Rock. I ended up heading straight up a fairly steep pitch for a short while unintentionally, where I came upon a burned down tent on a small rock ledge... odd. Its worth noting that as you are heading north west from Squaw Lake, there is a steep wall that gets cliffy on your left and a similar drop-off on your right (that leads down to the Cle Elum River), with a large relatively flat portion between them. Thus, if you just stick in the region that its relatively flat, you will head in the correct direction towards Cathedral Rock. The relatively flat region was snow covered and you won't see much dry ground for the rest of your trip up to Cathedral Rock. Be careful through this portion, the snow is melting and there is a lot of water running beneath the snow fields (see pictures). You could easily punch through into whatever lies beneath. Many of the boot tracks I saw were walking down the middle of open areas where it was obvious the melt water was running directly beneath, yikes. I stayed closer to tree lines where I could see patches of ground and gauge the snow depth while listening for areas where the water was running.
After a couple miles on snow, I could see Cathedral Rock and basically just headed straight for it. Without the snow, I believe the trail would continue and link to the Pacific Crest Trail (PCT #2000) before turning left and passing by Cathedral Rock. I hiked to the base of Cathedral Rock, ate lunch, and saw who had left the boot prints for me; another solo hiker with a split board looking to get a few turns. We exchanged pleasantries and he noted that he had been watching snow break loose on the peaks across Deep Lake and that it might be a little unsafe with how warm it had gotten and all the movement. He headed on to Peggy's Pond while I decided to call it a day, get back over the snow fields before conditions got wetter and make the drive back to Seattle.
By this time it was almost noon. Even after a mere 30 mins at the base of Cathedral Rock, I struggled to find my boot path as the sun had melted, and camouflaged, my tracks into all the other snow dimples. I picked my way back over the snow fields and knew if I stayed on the shelf I would end up back at Squaw Lake where I could pick the trail back up. I cliffed myself out by being a little too high on the ridge that lies behind Squaw Lake but was able to back track and get down to the lake easily enough. Depending on how much snow is melting and where you think the trail is, you might find yourself crossing substantial streams running down to Squaw Lake.
After Squaw Lake, I quickly descended back to the trail head and on my way passed a group of four skiers, one rock climber, and a couple hiking groups all on their way up. It was around 2:15pm when I got back to the car. After a short break at the car, I was zipping back to Seattle and destined to sit on the 520 for too long due to i90's construction. All-in-all, it was a great outing with just enough questionability to make for a tiny adventure.