I see more and more nurses exploring this option as baby boomers continue to retire in droves with only social security to support them.

But before the debt gets too deep, beyond what's escrowed of last and security, at some point you have to move forward with removal if the tenant cannot at least submit all rents to catch up.

SOURCE: MBA, Federal Reserve Board of Governors, Wells Fargo Securities, LLC, Intex Solutions, Inc., and FDICGovernment-sponsoredenterprises(GSEs) – Fannie Mae and Freddie Mac Fannie Mae (FNMA) and Freddie Mac (Freddie) continue to maintain a dominant market share among multifamily lenders and both have proven to be reliable sources of financing through numerous market cycles including the last prolonged recession.

Very smart of you to be learning alternative ways to secure your financial future, as medicine is certainly changing.  

I love the fear of loss technique.

With that strategy you are the bank and have the lack of liability and headach like a bank, yet your investment is ultimately secured by real estate.

IRS rules prohibit you from pledging your assets as security for the 401(k) plan's debt.While non-recourse loans are available, the underwriting is pretty conservative for this type of loan.  

(Since commercial financing can difficult to secure) I'd use the first floor or main house for the business and live either upstairs or in the mother-in-law suite.

Yes, that's the preferred technique.

I learned from on landlord on BP that charges a break lease fee that is almost close to the rent amount, thus allowing him to legally keep the security deposit in the case that the tenant breaks the lease.