These areas are already growing rapidly in development, appreciation, and tenant demand with plenty more to come. 

Investment Info:Single-family residence buy & hold investment in Grand Rapids.

I think it is worth looking into Santa Maria as well since it has been rapidly growing and gentrifying.

With a HELOC I should be able to throw rental income, double triple payments, from both new and current properties, to pay down the HELOC rapidly with the added security to pay as little as the minimum HELOC interest premium if needed.

@Liosbel Gonzalez I can completely attest to the rapid growth and high demand the Austin market is experiencing right now.

That area is rapidly developing. 

A major issue in Grand Rapids may not even register in Seattle.

Indianapolis is rapidly reinventing its downtown, with vigorous levels of rental apartment and condo development—prompting a construction boom in downtown offices.

I can speak to areas like Cobbs creek, Germantown and the far NE that, IMO, that have and will continue to see rapid appreciation in the coming years. 4.)

Seems like a good area in between Grand rapids and Lansing.