To get a taste I'd recommend acquiring a multi w/value-add (lots of sweat in other words) in a B+ area wher you can live and rehab and above all, LEARN as I've observed over he years it's not how much capital one has at their disposal but knowledge that will ultimately yield you the "cash-flow" you're aspired so to grow.  

I've read a few blogs, been to a courthouse auction to observe, and now found this great resource. 

I agree with your observations.

Your observation that that specific TKP is niche is probably correct.  

Observe her employer...and take it from there.

I knew my target market was the University of Maryland Medical Center as I observed people in scrubs wandering their way to the block adjacent to the block where I bought.

There isn't any scientific study or stats that I know of.Merely pointing out the observation of my wife and I as we have been looking at properties over the last 4-5 years. 

I like @David Song observation.  

The absence of a thermostat is something you could/should have observed when viewing and signing the lease and when you discussed heat.

In my opinion and from what I've observed there is a strong demand for rentals the ones that go the quickest are the 2/3 bed one baths from 500-800 a month.