Some of the properties I am investigating back up to the tracks.  

You go to some weekend home owner classes and learn how to own a house:)Here is one of the links but if you are looking to buy this might be something worth investigating more for both LA city and county areas.Good luck with your search!

Even if it's your word against his, he does not want anyone to investigate this.

So if you suggest to me areas that have better cash flow on average than Dallas Fort Worth, please let me know so that I can investigate for next time.

Perfect, because now is the time to consider renting out both sides of the duplex while you begin to investigate your new single family home.How does this phase work?

@Jason Downing , if I were starting over again, I would decide what market I want to go to, investigate crime rates, unemployment, etc. then start reading about every house on the MLS or Zillow, Truilo etc to get an idea what the market is then start looking at rent prices until you have a good idea on your own what houses are worth and what they will rent for.

I want to investigate this ASAP and assist in any way I can with your closing. 

Is there some kind of online private investigation resource?

People fail to investigate other sources of money before going "hard".

@Russell Adams the first step is to investigate the different kind of owner financing options available that work for you and the seller.You are correct, you will probably want a lawyer to go through your paperwork, especially if you haven't done an owner financed deal before.