Been riding this route since 1972. Road to Paradise has definitely deteriorated since then. Used to be perfectly smooth, now filled with bumps and cracks from tree roots and wear. I suspect budget cuts keep roads from being maintained. Lots of good corners though and spectacular scenery.
I did the 2nd half of this route thru Mt Rainer national park which costs $5 to enter, this is a mountain road as good as any top Alpine road, which I have rode many time
A very beautiful road with dramatic views of Mt. Rainier as your nearly constant companion. More traffic on the Paradise side of the ride, and less on the Hwy 410 side above Enumclaw. You can do this in a day from Seattle if you're mainly focused on riding. There are many good roads you can link to from this (Chinook and White Passes, etc.). If you're visiting western Washington, and the weather is decent, this is a must ride.
Love to do this one when I'm getting squirrelly. Used to do it on the Street Glide I had with friends on sport bikes. But the bike is gone now and will be doing it as soon as my new Multistrada 1200 gets here! Very few cops(occasional presence), challenging twisties and scenery makes this one a must do. Especially in summer months