I'll be heading out to Wenatchee from the Tacoma area. When we lived in N Seattle, we used HWY 2. Now it looks like I-90 to Cle Elum to Wenatchee via 97 is the way to go! How is the area thru the Pass...
We've had no issues going either way over 97 to Wenatchee. Do it a couple of times a year. If you keep a look out ahead for slower trucks you should be able to time it passing them ok. But I'd really look into the cooling problems, as that isn't good. You could even get down to 45 on busy holiday weekends anywhere around here.