We just drove Hwy 20 to/from I5, during the day it's fine. There is a section that is/was washed out and the lane narrows, one area there with some construction it's a rather tight corner, but beyond that is fine... during the day. Few years ago we did it at night and I will never do that again.
I can't comment on Hwy 20 into the Cascade, been to many years since I've driven that.
Two Wire Fox Terriers; Sarge & Sully
2007 Winnebago Sightseer 35J
2020 Jeep Gladiator Rubicon