You aren't very far from the Columbia River Gorge, absolutely worth a day trip. I'd drive west on the WA side of the Columbia, then cross the river southbound on I-205, then take the scenic highway eastbound, and see the waterfalls, dams, etc. Check out:
There's not much in Selah, but you could drive also to Yakima...
Expect hot weather but, unlike Ohio, it is a dry heat and much more comfortable.
I'm assuming you will have access to a car. If not, perhaps others can discuss any tours.