you have to go to the owners of the buildings.. one place there are literally thousands of these types of props that would be good wholesale targets is south side of Chicago

Find out:Your target area; ALL costs of a mail campaign (list, letters, postcards, necessary office supplies, postage, etc); budget for 6 months-1year of mailings; develop scripts for prospective sellers (what to say to them); learn to track responses, follow-ups, conversion rates, overall campaign effectiveness, etc.Build your team; title company, RE attorney, cash buyers, closing agents, etc.This list may seem long and overwhelming but if you're looking for a "secret sauce" in this business you wont find it.

I want to break that down by area code to be able to tell what areas investors are targeting.

Not everyone realizes that it's possible to acquire real estate for so cheap or they figure that it's probably not going to happen for them anytime soon in their target market because demand is so high.

If that's the case , of course the Bank is going to tell him to go pound sand!  

In large cities, identify neighborhoods that are close to public transportation, as they will become prime targets as population explosion in urban centers continues to push people outward.

Outside of ARV's and basic area details....what are some other important factors, data, numbers, demographics etc - I should have a good grasp on when considering an area to target?  

To see whats really happening with downspouts,gutters and puddles you have to BE there in a huge pounding rain,,,just no other way. 

Ask neighbors in the target area if they know of anyone looking to sell.

Does your target buyer value yard space?