Places I would check out:
Slidell, LA. 15 miles from New Orleans, super laid-back, small-town feel, amazingly friendly people. Don't get me started on the food. I usually weigh around 215 lbs. When I lived down there I ballooned to 270.
Asheville, NC. It was heavily suggested for me a few years ago when I asked. It didn't click with me, but it must be good because everyone talks about it. It's not really close to larger areas, but it's within a couple hours of big stuff.
If you want consistently temperate weather, there is nothing I can think of that beats central CA coast, but you have to be pretty far away from metro areas to be affordable.
How about Albuquerque? It can get pretty cold given the elevation, but not any worse than some winters in OK. Close to Santa Fe which is a lovely area. Same basic recommendation for Flagstaff.
My normal recommendation for this request is Austin TX, but housing prices have gone nuts. Still, the surrounding areas are lovely. The town is awesome, and some of the communities nearby are exactly the opposite of what you think of TX. Hills, green lawns, trees, lovely. Kyle, New Braunfels, and San Marcos have remained relatively inexpensive and are close to both Austin and San Antonio. Killeen is a bit off the beaten path, but cheaper.
Generalizations: East coast will have all the seasons, it's just that they are all more humid and the average temps go up as you go south. PA is 70-90 degrees in the summer and 20-40 degrees in the winter. It's the same in GA, just 80-100 in the summer and 40-60 in the winter. West coast will tend to be less humid and have two basic seasons; false spring and fake fall. I used to joke that Los Angeles had 50 weeks of the year at 72.367 degrees, then one week of winter that was 50 and one week of summer that was 95. Relative humidity was negative 20% except for the two hours surrounding the four times it rained each year. San Francisco is the same, but replace those numbers with 65, 45, and 85 respectively. Seattle is the same, but add rain and make those numbers 60, 40, and 80. San Diego is the same, but the numbers are 80, 60, and 95. It has to do with the prevailing currents of the oceans. Atlantic flows S-N bringing warmer water and higher humidity. Its also why you always see hurricanes hitting the south-east of every continent. Pacific flows N-S bringing colder water. Lower humidity and more stable temperatures are a typical result. I mention all of this because you mentioned she doesn't want cold and you don't want humid. The easy button is to go west and deal with either desert or CA housing prices, or go east and south and deal with humidity.
In the middle of the country it more or less follows the predominant jetstream which is why you get freezing temps in OK, but up in Seattle they rarely do. Your climate in OK is more closely related to KY/southern IN than it is to something along your same latitude like Atlanta or Las Vegas. i only mention that to suggest that as you go closer to coasts you can go a bit north and not risk going any colder than you are now (with obvious exceptions for altitude) I'm thinking Virginia, Utah, Kentucky, etc.
I won't ask your political stance since it's irrelevant, but are you looking for a more conservative area? Liberal area? Mix of both? The reason I ask is that you can likely find a climate you enjoy in either Portland OR or Springfield MO, but given their differing cultures and political tendencies, one might be a great choice and the other one a terrible place to hang your hat.