If we paint a different color - its generally a small area, like a bathroom (light blue/ gray). 

Haslett has some blue collar areas with some nice multis.  

Is there something about the yellow color which makes more it effective than say a white paper, brown paper or blue (my personal favorite)?

Good blue collar is good.

But if I were to do anything, I'd just go with a lighter trim color to give more contrast between the trim and the green on the home, maybe a light gray or even white. 

My wife does all the cleaning between rentals.But to answer your question, the closest thing I have found to a centralized database is a site called blue collar housing without the spaces. 

I just did a portfolio in Blue Ridge, TX similar to this earlier this year. 

Some more positive factors are stability, relatively well-behaved tenants (especially compared to "blue collar" neighborhoods in the US - the concept of "war zones" really does not exist in Japan), and a mature market.

If you get an upgraded membership, there are calculators on BP under the "Analyze" tab of the blue navigation bar.Otherwise, a quick google search for "real estate investment calculator" gives a ton of options:http://www.goodmortgage.com/Calculators/Investment...http://investfourmore.com/rental-property-cash-flo...There are two.

It's been nearly two years since I graduated from college with a degrees in economics and psychology, and my time since has been split between two blue chip corporations in the energy space.