My first thought was Wash st. Somewhere along the Columbia river Longview maybe. No state taxes (yet) still not to urban. within 50-70 miles of coast is temperate without being too wet.
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I've been doing some of the same things lately. Wikipedia has data available on most cities over 30,000 which includes demographics, weather including avg hi's and low's monthly and snowfall and rain days. I simply started looking at the maps and checking towns to get a better idea of the norms. Next year we start rolling and will spend 3 years or so deciding where to buy a cottage to finally be planted under and we will continue to roll till OUR wheels fall off.
I also had found some sites, I can look them up iif you need them that give cost of living averages based on property values, taxes etc , it may take a while.