I have several friends that attended Linfield a while back and it wasn’t overly preppy at the time, but things may have changed since then. The eastern WA region is indeed pretty different geographically and politically from the areas closer to the coast (though most college campuses lean liberal everywhere). You may find it more similar to Colorado than you’d like.
And I do think PLU and UPS are good fits for you if you can make the money work.