On the way to and from Seattle we had a couple meals in Moses Lake.
Dinner at Pho Saigon was decent -- a little sweetened-up but more than serviceable, especially after a 7 hour afternoon on the road.
Lunch on the way home was at Tacos El Rey. Tongue, tripe, barbacoa, carnitas tacos. We ordered twice. Yum. A great spot; we'll be back, if only to try the massive bowls of menudo.
Both of these places are just fine, especially if you're not up for the usual road fare. I'd also like to add that the service at both was gracious and efficient.