Location is residential with a park a short drive or long walk away.

The truth is most methods work - cold call, direct mail, referral programs, driving for dollars, etc.

You might want to visit Detroit if you have not, and drive around the different streets in the city- but I warn you it is very dangerous in many parts.

I remember I used to drive by my first rental property often just to make sure... - IDK, that it was still there??

A good investor agent can find deals for you, you can cold call, drive around, and scour city data.

I mean drive up and down the Eastern part of the state until you find an area that has not been completely discovered.

I can't figure out what the economic forces are in the community driving the high rents and relatively low purchase prices.

They don’t want to drive more than an hour each way every day.

I sold ownership in one of the companies I had invested in the UK and took out some stock investments that I had. 

I would recommend doing a "reduced" (~60%-70%) leverage refinance which would help drive your rate down as much as possible and hopefully still maintain the cash flow that you would like to have, especially since they are free and clear.If you were to go the portfolio route, I would confirm with the lender you use what their 'occupancy requirement' is.