As far as spacing goes I've seen the table that provides spacing requirements on the FCC's website. Problem is I'm not sure how exactly to find the distance to two sites. I got most of the steps right, didn't I? There are two issues I could see,As Bongwater points out in a couple of posts, it's not that simple. Frequency changes and upgrades require a lot more than simply willing it to happen. FCC R & R contains mileage separation requirements... look 'em up and do your own calculations. I once was provided a proposal to move one of my stations to NEAR Seattle, and it involved something like 20 different moves within Washington and Oregon, in several steps. And that was several years ago. Every time a station upgrades, it reduces the opportunity for another to move.
The 104.5/104.7/104.9 situation involves more than just Aberdeen, Eatonville, and Covington. There's Wenatchee and a few others to consider. Covington and Eatonville are singletons; you can't take away sole service.
1. I don't think there's enough space between KNRQ and KVAS if KNRQ were to move to 103.9. KVAS could possibly move to 97.5, but I'm not sure if that would comply with the spacing requirements to 97.7 in Oakville.
2. There's a class A in Roseburg that would have to move off of 103.1 to make the upgrade of KYTE possible, but if KSKR could operate on a Portland frequency as a C3, then moving that to 103.3 or 103.5 shouldn't be an issue. Come to think of it, I'm not sure if you could do a first-adjacent A to C0 from KYTE to KRSB.