Here you go:
https://ridewithgps.com/routes/39757957
Hope you can open it whether you have RWGPS or not.
The roads up to Sultan are quite ordinary. I've ridden them many times. Beyond Sultan, I used to ride Hwy 2 at least once a year, all the way to Wenatchee, but the last couple decades it's become annoyingly busy. I've shown some off-Hwy work-arounds, which I've also ridden because of the traffic. They are fairly strenuous, the Kellogg Lake one more so, the one ending in Index is actually pretty good and a very good option. The last 10 miles into Skykomish are shoulderless. OTOH, it's only 10 miles and quite flat. Hwy 2 traffic is quite weather-sensitive. Much of it is people going to eastern Washinton either to escape the rain on one side or the other or for weekends or holidays, so think about things like that when deciding when to do it.