For example, maybe you will get to 10, 20, 30 houses and then find an owner who has a large portfolio and all of a sudden you are at a high door count and now need to hire, need to build your policy binder, and all the other stuff that comes with running a business.

They bought their house near Lucca, Italy.  

You do not actually need any income if they have high enough income to afford their bills plus your new house.

On the 15th year, the investor and I will discuss together whether we want to sell the house OR continue receiving cash flow.

Pros: the cabin will be able to house our entire family, easy process to refinance.

Quote from @Vanja Dimitrijevic: Hello, I've been researching BP podcast and resources and am looking into buying another property to downsize from the current one but wanted to use the equity in my current house to purchase a new house in the area.

I would keep rent a little below market, then split the monthly bill between the tenants on top of rent.Old houses in cold climates get expensive in the winter.

I have considered it but I keep things at a flat rate for the exact reasons you stated.I want people to get the exact price when they stay at our lake house.

My plan was to purchase a lot and build a foundation, bring in a doublewide/manufactured house. have it placed on foundation and have a structural engineer reclassify it as fixed real estate. then, I would refinance. 

This approach could keep things straightforward while accommodating their need for housing.