If you do the route frequently, fly so you'll rack up the miles and segments for elite status. You might drive it once just to see what it's like. I'd recommend that you get off I-90 in Cle Elum and take Blewett Pass to Wenatchee, cross the Columbia, and take Hwy 2 to Spokane instead of taking I-90 the whole way. Hwy 2 is more scenic and you'll drive by Dry Falls , a spectacular formation that used to be the largest waterfall in the world when it had water in it. Dry Falls was created by the same glacial floods that carved out the Columbia Gorge. You'll see a very different side of Washington than you see on the west (wet) side of the mountains. (Dry Falls is about 2 miles south of Hwy 2 on Hwy 17 just before you cross Banks Lake and get to Coulee City.)

The Cottage Cafe is a decent 24-hour dinner in Cle Elum. Also, Wenatchee has lots of places to eat and will be about half-way if you drive. If you're coming through at lunch, try The Cellar Cafe on Mission Ave. for good soups, salads, and sandwiches.