I called the most recent one back because his letter stated that Land Records indicated that I was in default (???????). 

Three indicators I think you should watch are population, crime and job stability.Population MigrationIf people are moving out of the area, the housing prices and rental rates are likely to fall.

Bryan, best advice I can give you is to read to docs very carefully and therein you'll find how nervous they really are (LOL) ....okay,Lending and borrowing under open lines of credit is really an exercise in phycology almost as much in finance and banking.I assume were talking 1M+ as you didn't indicate the stress level.

Three indicators I think you should watch are population, crime and job stability.Population MigrationIf people are moving out of the area, the housing prices and rental rates are likely to fall.

Proof of funds is a document indicating that you personally have the funds available to close the deal using your own cash.  

This will give you a clearer indication of what you will net.  

Gross income 3x rent is the gold standard as many have indicated; this tenant clearly does not qualify based on this measure alone.

However, it is a very poor indicator of investment worth, useful only as a "bird's eye view", and only as a very, very loose guideline.  

I really hope he takes the offer but he hasn't indicated that he has.My contractor is working on the sump pump and ventilation now and he just sent me a text complaining about the tenant. 

As @Shawn Holsapple  indicated,  your targets are attainable.