My friend and I did this hike over Thanksgiving weekend, and were both really surprised by the challenge of the hike, danger of the trail, and lack of information about access to Sykes Hot Springs.
Let me start by saying this is a hike in only site, and the hike in is no joke! I had read about it ahead of time and knew that it would require some serious elevation gain and was rated as an "intermediate" hike. What I found instead was a punishing almost vertical climb up a narrow (in some places less than 2') trail that hugged a sheer drop thousands of feet. If that doesn't scare you off, then the fact that it started raining during the hike and the mudslides began to wash out what little trail there was should.
We started out early in the day, hiked until sunset and only just made it to Terrace Creek camp. We had hoped to make it to Sykes Hot Springs, but when it started raining in the early morning, all we could picture is getting trapped on the mountain if the trail washed out, so we started back at first light. Again, hiking up had been scary but hiking back as the rain washed over our boots was nerve wracking.
For the sites themselves, there is no running water, but there is a creek you can use with a purifier. There is one open air toilet that serves the whole camp on a hill above the sites. No trash service is available, you have to pack out. No fires or gas stoves without a permit.
I wish I could say I'd brave this hike again and finally make it to Sykes, but I can't.