This is a big-bike friendly route from Exit 42 on I-90 (Tinkham Rd) over Snoqualmie, Stampede, and Tacoma Passes. The route passes near Windy Gap, Pyramid Peak and the Naches Trail.
I’d say it’s best for advanced beginners and above. There is a rocky climb from the southeast end of the Stampede Loop up to the high shelf roads that parallel the PCT – rd 7036. There isn’t that much loose rock. You just need to be comfortable picking a line and sticking to it.
The route is 151 miles long with 30k ft of ascent/descent. There are numerous escape routes including Greenwater and FR19 to Clifdell.