@Gerald Harris suggested a good strategy for finding those.

Here is my simple wording.  

Anything that seems too good to be true is, plain and simple.

My suggestion is that if you are going to make this a long term endeavor you definitely mention that.

Be flexible and respectful to both the residents and to the employee of the company actually paying the bill.I know this sounds incredibly basic and simple, and it is.

I'd suggest you meet Julie Hudleson Schmidgall with METEC.

Its simple arithrimetic but often there is an angle and no prop is the same.  6)  good beginner rule I use for myself is that for a buy and hold multi - if it needs more than 10k of work its probably not a great FIRST investment.  

Someone on BP may have a different suggestion on the later.

In a perfect world an assignment (like @Chris Seveney suggested) would be recorded with each transfer of the note but in reality that does not occur.

This gave many the false sense that real estate is simple but its not.