Looks like you've got a great trip planned! And you meant 'Cle Elum', correct? I don't recall just an 'Elum' town/area.
I wish I saved the routes we did when we used Moscow as our base camp area. I recall doing rides around Colfax, Potlatch, Palouse, Starbuck and Dodge. Great roads and some scenic areas!
Not sure of the route/direction you'll be coming, but check out the wind farms from Vantage westbound to Ellensburg/Cle Elum. Here's a ride vid I did not too long ago...
https://youtu.be/uwQcWR27-jYAnd if you intend to make it to the Cascades, ie Snoqualmie pass area, be sure to check out the backroads off I-90 to Denny Creek. Ride vid is going eastbound but worth riding westbound too...
https://youtu.be/afeHrx-KNDgWe did Mt Rainier CW loop last weekend if you have time or want to see what the conditions looked like...
https://youtu.be/hF5w4YhpLhYI'll have to find time to edit & post up the Rowena Crest roads we did a few years ago but since you're in that area, you might have ridden it plenty of times.
Have a great trip!
Robert