Then I noticed on Zillow how many properties are up for rent, so I then check the historic population.

The only problem with investing near a military bases, is the possibility of the base being shut down and the population drops suddenly.

PA is the 5th largest state of the 50 states by population, only CA, TX, FL and NY are larger. 

@Jon S. your population chart is a bit out of whack.

I don't know much about your area so the best start would be find a local real estate agent, talk to them about the area you want to invest in and do some research on the area where you want to buy, is there population growth, job growth etc...

With a population of just over 8000 and being situated more than 300 miles from a larger population center, Caribou is too rural for most national lenders.Stephanie

@Jeff Burdick: I believe this is a map of changes in population.

We currently live in rural MN, but want to relocate to a larger city in Minnesota (ideally somewhere in the Twin Cities Metro, but maybe other population centers like Mankato, Duluth, etc.).

Boise is similar, lower cost of living, lots of new jobs and a growing population.  

I would not do an all induction cooktop if marketing to an older population.