Sam and Bill are a pair of criminals.  They are not the smartest or most ruthless pair either. They just like to think that they are.  Sam also believes that he is the brains of the operation.  Considering Bill's level of cognitive overhead, it's not hard to be the brains of the operation.  Sam also likes to use random, big words to make himself sound smart.  

The quote that you are talking about is in the third paragraph of the story.  Sam is explaining to his audience why he and Bill need to kidnap and ransom a child.  They need some extra money in order "to pull off a fraudulent town-lot scheme in Western Illinois."  What that likely means is that Bill and Sam are going to run a real-estate scam of some kind.  It's obvious they are going to commit some kind of fraud.  Houses are built on lots, and that's what I think "town-lot" is referring to.