Seattle is a bit closer, only ~2 hrs, I90 up to Snoqualmie Pass, out to Yakima. The western side of the pass is gorgeous, especially in the foothills. Once you get to the eastern side of the pass, it turns into high plains and desert.
Hotels are only about $100 to $125 per night in Yakima. Hop Union has shuttles going back and forth.
It gets HOT (95-105 or more), so dress appropriately and drink lots of water.
Some folks in prior years thought they'd be able to save money by camping in a tent. No way. An air conditioned RV WITH a shower would be ok, but anything less will have your classmates plugging their noses and staying a mile away from you.
HTH-