Our best has appreciated ~$4K/month over the holding period (21 years).As for difficulty extracting value, I am not going to say it is as easy as cash flow that gets put into the bank by the tenants, but it is not super difficult. 

In Beckley, WV, there are strong extraction, healthcare, government, and service professions, but most people see WV and only think “extraction.”

Would we jeopardize anything getting a mortgage and extracting capital to invest elsewhere?  

Recently i pulled all the multifamily 2-10 sized units, was a pretty simple data extract. 

Note with the current RE rules, I never expect to pay taxes on my appreciation (rules can change) even though I have extracted appreciation multiple times.I am not stating my RE route is passive. 

I intended it to be a BRRRR that was unlikely to extract entire investment.  

It is by taking equity, extracting out via HELOC/REFI/Sale, that you effectively grow your net worth.When you monitor ROE, you can see which properties are doing well and which ones aren't.

However if I do a BRRRR I can achieve infinite return by extracting all of my investment.

Tertiary markets in KY with an abundance of brick 4plexes built in the 70's, for which I had to hire a software engineer to forcibly extract property data from county sites because the records are not available on any batch data services, just one off searches on county records. 

A good real estate agent will bring value to a property owner and get their property sold for the highest price.A good wholesaler will get the lowest price and extract the most value away from the property owner for themselves and the investor.If a property never hits the open market there is no way its true value will ever be determined.