South of Seattle Rainier looms; to the east Snoqualmie Pass. Between Seattle and both locations there are lots of roads. Between Rainier's east side and Snoqualmie Pass however there are not paved roads. Closely staring at maps for Forest Service roads that connect the two (I am pretty blind) revealed that Greenwater Rd - Whistler Creek Rd - FS Road 7036 connects all the way to Forest Road 52, which is a part of a well trafficked route which connects Stampede and Tacoma Passes.
The first paved part of the climb (Whistler Creek Rd) is fine. The day I did it there were lots of people shooting guns. After you hit the dirt (which is not especially rough, but was somewhat loose). The early slopes are steep but smooth.
The views only get better. Be sure to bring an easy gear. It gets a bit rougher but isn't too bad.
You pass along the ridge momentarily. The views are dope.
Descending the north side to FS 52 is rough. I got rowdy and took a tumble in a rut (38mm tires at 40 psi not advised).
After you hit FS 52 you of course have lots of options. I did Tacoma Pass, then rode to Hyak and descended back to North Bend on the rail trail.
As far as route revisions are concerned, it would be cool if somehow Highway 410 were avoidable. From Enumclaw to Greenwater it seems totally unavoidable.