It just needs a diverse economy and a growing population to support you in good ways.  

Big booms and busts based on fantasy and dreams.If you're saying it's speculation you'd be wrong in the sense that we're making purchases based on good market fundamentals (population consistency/growth, increasing development of the area, planned development like parks, etc)And within those fundamentally attractive areas, we try to find attractive properties that we negotiate great prices on.

Takes about three days to populate, but once it does, you generally get better people from zillow and trulia.  

I see new growth beginning in Elkhart and Goshen, but is Southwest Michigan (Berrien County) going to continue to lose population?  

They like to see certain population levels, higher median income, traffic count increases etc.Generally if an area is rural or far out suburban with limited growth those areas do not attract the national tenants.   

So, with population rising and SD not getting any bigger; would it not be safe to assume that it's Real Estate will remain among the highest in demand?

Turn the whole place into a haunted house.Info about the area:  The immediate area has (-)2.2% population growth years 2010-2014 and is not a heavy industrial area.  

The population growth stats are really where they need to be for REI.  

Far along in my real estate investing career, I envision owning larger apartment/dorm complexes near universities with a high international student population, and making a business of facilitating the study and exploration of foreign students in the US.I look forward to meeting all of the BiggerPockets members in the Brevard County (Melbourne, Palm Bay, Titusville) area, and hope to learn the skills and confidence necessary to be successful in the business!

You should be looking at whether the populations are growing, whether there is job growth and if income is growing.