Where do story ideas come from?  The answer to that question is unique for each story.  In the case of Gamble's Run, the idea began in 2006 with a short article in The Ledger, a small local newspaper.  It featured a little known historical site called the Slave Canal.  The only reason it was in the news at all was because legislation had been introduced to rename it the Cotton Run Canal.  The name Slave Canal had been deemed 'racially insensitive'.  The idea was strongly opposed by the local residents, many of whom were descendants of the slaves who dug the canal.  Their reply...Don't Mess With Our History!  The idea was quickly abandoned.
That article resulted in a short story called The Slave Canal.  A few years later, the idea for Gamble's Run was fully formed.  If you're interested, here's the link to the original article.http://www.theledger.com/news/20060115/residents-dont-rewrite-slave-canal-history