There is always a great divide on where to buy investment property. There is the never ending balance of do you invest for cash flow or do you invest for equity. There is no right or wrong answer and each individual investor has specific goals, criteria and priorities in life that determine their decision and form their business plan. In this article by Aly Yale, she provides where the highest yielding rental markets are currently in the US.
Like any investment, this will be subject to change, but these areas would not be a bad place to start getting boots on the ground if you are out of state and start looking into making double digit returns