It is currently improved by a 700 SF single family dwelling with historic designation.

The one exception is the house I own in a historic district in Fort Worth, which is the "bluest" political zone in the city.

While that's fine, historically property-management companies that serve smaller rentals eventually fail for one reason or another.

Projecting out 10% historical annual returns until your retirement?

Purchases are about occupancy intent, refinances are about current/historic occupancy reality. 

Also, historical buildings have their own set of requirements and hoops to jump through so keep that in mind as well2.

Historical appreciation = 3 percent.

Their appreciation historically has provided a better ROI for financed buy n hold than better cash flow locales (which is built into the price and why they are difficult to cash flow).My ideal areas are not necessarily your ideal areas. 

Not to mention you get to lock in a historically low interest rate for 20+ years (guessing it's a 30 year fixed rate loan).

So I'm aware that Coldwell Banker can pull up all types of information and zoning maps and square footage and historical sales prices and whatever.