Looking for a Homebase Homestead

My wife and I are aspiring photographers.  When I retire from my mundane job about a year from now, we want to take our act on the road to do our photography thing.  We're realistic enough to realize that being on the road year-round is just not practical, so we're looking to relocate to somewhere with mild Winters but without subtropical Summers. (I'm the original Ice Cream Soldier™ and my wife's heritage is Swedish/Finnish, so she's also heat & humidity-averse.)

We're both Washington state natives with limited travel experience outside of the West Coast and the Intermountain West, so I thought I'd ask for opinions here?  If it's not a proper topic, please feel free to moderate as you see fit.

Criteria
=====
 * U.S. Lower 48
 * Mild climate
 * Relatively low land cost (In comparison to the U.S. West coast, say < $5,000@acre.)
 * Good water
 * Flexible building codes
      - Friendly to following construction types:
          + Log
          + Timber frame
          + Strawbale
          + Tiny homes
          + Owner-built
          + Earth shelter
          + Slip-formed/Tip-up masonary
          + Off-grid systems
 * Homeschool-friendly
 * Nanny State free
 * Permaculture friendly -- of course.
 * Low crime rate
 * Friendly folk
 - Good wild game populations
 - Good fishing within reasonable travel
 
 
I was born & raised country but have been living in town most of my adult life.  My wife is a from the 'burbs, but likes the country lifestyle.

Our current plan is to sell our house and get an RV.  We'd like to acquire a small piece of acreage as soon as possible to develop as a home base.  We'll put a pole building on it to start with to park the RV in and to develop into a workshop/storage area with a future attached house or cabin. Since it will be unattended for extended stretches we're definitely interested in an area with low crime rates and friendly folk who actually neighbor. (That's getting pretty darn rare hereabouts.)  We don't accumulate a bunch of valuable "stuff," (What we have will go with us in the form of cameras and laptops.) so it's more the hassle of repairing damage done by chuckleheads that we're worried about.

OK Permies, what say you?

Does such a pie-in-the-sky destination still exist in today's world, or am I seeking that which is no more?

Welcome Richard!  You're aiming for a fairly commonly desired climate.  Mild winters, mild summers, not high humidity.  You may want to define your idea of mild.  I think of a mild winter as one where we rarely hit -10F.  Unbearably hot is 85F.  

I think you'll find plenty of places with acreage under $5k per acre if you get 5+ acres.

My guess (based on very little knowledge ) is that you could hit most of your desires in the West Virginia/Tennessee/N. Carolina area if you play with elevation.  I'm not sure about the humidity though.

Many of your considerations can vary greatly in a space of 20 miles (good water, building codes, crime, neighborliness, hunting, fishing).  

I'd do some research on which areas of the country meet your climate needs (cold, hot, humid, dry, rain, snow) then narrow it down farther by natural disaster worries (if you have any worries).  Proximity to health care and airports could be important?  Keep in mind that two spots in the same county at different elevations will have different climates.  After picking a number of areas, then investigate them each for your other concerns.  Easier to research topics are probably building codes, price and crime.

Then take some vacation time and visit them.  Look at homesteads/houses/lots for sale and see what your money gets you.  Explore the downtown and talk to the locals.  See if any of them feel right.

I don't know what your criteria of too cold, too hot, too humid etc. are so it's hard to say where exactly would conform to your specifications. The sort of climate that you want is desirable to a lot of other people too so often those areas are pretty expensive. I would second Mike Jay's recommendation of the southern Appalachians at a high enough elevation where it's cooler, probably at least 2000 feet. Western NC has some of the best areas that way, but I know a lot of it's gotten pretty expensive, I spent some time in the Asheville area in the early 200s and I hear it's just gotten more and more expensive, possibly there's some areas in the NC mountains farther from Asheville where it's cheap, also look at southwest VA and the Cumberland Plateau area of TN. WV does have some areas with pretty cool summers but the winters there would be harsher than further south.

Really, most of the country east of the Rockies has either pretty cold winters, hot humid summers, or both.  Areas of the southwest at a high enough elevation to not be really hot in the summer could be another option, but the main issue there would be a lack of water.