Additionally, any tips for out-of-state investors would be invaluable.Thank you in advance for your help!

I work in and around the Osceola County, Florida area and I'd be more than happy to help out any person willing to learn about how they can grow a passive stream of income.

(additional info: changing the stairs or getting new ones would be a massive undertaking)

can do no income no doc at 30% down on the purchase providing 100% of the construction 

There is zero proof that card systems work better, generate more income or make life any easier.

George - I think that the owners most likely to seller finance a portion of the sale are those that have owned their property for a LONG time (potentially looking for residual income) and owners than own their property either "free and clear" (without a mortgage/debt) as they have more flexibility.

Does anybody know if my father can prove his income to a lender when I try applying for an FHA loan instead of my income? 

My family and I would live in one of the units in order to be able to do this, and there would be an additional 3 units in order to get the full amount of the FHA loan. 

I have investigated several out of state markets and have not found anything that I like better than what I am investing in now when comparing overall income, expenses, and the potential for appreciation.

For passive income you can look at REITs or DSTs as well.