It's a powerful part of the tax code that so many investors are unaware of.

Nothing will be up to code including the slab.

I'm unsure of the self promo rules.)

Meaning no part of the structure would be in the flood plain, rather built up to the current building code. 

Any suggestions on zip codes and realtors?

There are only 5 houses under $700K for sale in this zip code .  

Signage may be controlled by building codes in your area or special signage codes regarding heights, foundations, electric Lighting Etc...

You get grandfathered into the codes that were in place at the time, you get the old setbacks, you don't pay an architect, engineer, city and permit fees, plan check costs, school fees and other costs that will not come with an existing house.Not saying that you can't build new for less than a remodel, but not usually when you add in all the costs above. 

Then i connect it to my locks so that when guests check in, the door code is set to their phone number and it is set automatically.

When you get closer to the date you're ready to start shopping this area, I'll be happy to update the appreciation reports for any zip code you're interested in.