My goal is to generate cash flows in the future (15+ years time horizon). 

Maine is a great place to invest, so I'm really positive about what the future holds up here for me, and in the rest of New England as I expand my horizons.

Indianapolis can be a solid market for growth as it has a lot of new developments on the horizon with a $4B expansion to the downtown hospital (applicable for MTR tenants).

Since you have a 20 year horizon I wouldn't shy away from the leverage.

You have to have a long time horizon, and the property management will make a huge difference (for an out of state investor), as they will be able to correct issues and problems,  as long as they have an attractive  house in a solid neighborhood to work with. 

However, if you expand your horizon to B-D neighbourhoods than you will see properties in the $600's and the odd one in the $500's.

But there is good news on the horizon, potentially. 

Treasuries and other bonds are not in this list.With a 9 month horizon a rolling 3-month Treasury ladder would work well. 

In my opinion solely, if there are meaningful better IRR opportunities over the time horizon you are considering, then yes sell; otherwise no.

They may have found a job and if so a payment plan could be set with that knowledge or if prospects for a job are not on the horizon, we might have the discussion about them having to move out.