I am wondering, though, if I should be excluding any of them by population.  

The population density of the U.S. in 2010 was approximately 90% per square mile, but effectively we are supporting 400 persons per square mile for most of our improved land uses (adjusting for farming and gov't).

My main reason for wanting to know more about investing is for financial security, thats is why for my investments i want to pay cash, but before i get that far i need a lot more information. i have a wife and 3 kids and like in a small town with a population of 12 thousand. i love to cook and went to culinary school.

But that is out of 20 million population so your odds are 1 in 20 million population wise..

If your home is in an affordable area populated with first time buyers and lower income people than obviously interest rates increasing will make current prices less affordable and you'll have to adjust accordingly in order to sell. . 

The population has decreased in both Detroit and Cleveland between 2010 - 2013, but Atlanta's MSA population grew by 236,214 between 2010 - 2013.

Generally, I check the neighborhoods with AreaVibes.com, I check the rentals with CraigsList and Rentometer.com, I check the past sales/comps with Realtor.com, and I check population growth with USA.com, or city-data.com.

I'm an engineer by training and put a lot of stock into mathematical modelling and analysis.In many aspects Canadian real estate is not that different than U.S.A. real estate, but there are some significant differences: the national market, and most individual submarkets, are smaller (~1/8th the population); prices are higher (we did not experience a corresponding correction in 2008/2009);taxes are {generally} higher;lending is different: {mortgage} lending rates are lower; mortgage terms are shorter; qualification requirements seem to be a little more stringent.Le Bon Homme Sept Heures is a fictional folklore character used to frighten children in an effort to make them more wise .... there is a similar character in English, but when I wrote the above, I could not recall the name ... and I'm still drawing a blank.

Plus, according to your site, with 86 private lenders, and a population of 11,192 (per 2012 US Census), private lending on a per capita basis in Spencer, Iowa 51301 must be the dominant industry.

Go to counties that are not heavly populated as the competition is less.Know what the right of redemption period is.Do you have to pay cash the day of the auction?