Using AI ;-) the answer is ""Detroit has approximately 102,330 vacant housing units, which is 28% of the city's total housing stock."

Obviously with notable exception like the crash of 2008 that hit nationally. 

I have one tenant who is a god send compared to most, he accomplishes nearly ever repair I need, even did an HVAC unit. 

Quote from @Olga Daisel: @Randall AlanI agree with Randall on getting more details, $7K gross a unit btw is a great gross income.

I am conflicted on whether to use the 500K on one big property (ideally multi-unit) or buy several smaller properties.

The loan is with you, not with your tenant, so none of that means anything to them - in fact because you live in one unit and it's under 4, if you were self-managing you don't even have to abide by fair housing laws (at least on the federal level). 

And it's not only homes, it's all the infrastructure a city needs.On the insurance issue, I think this may be the end of national carriers.

They are a national organization that promotes all kinds of creative real estate deals. 

Cleveland currently has one of the lowest price/rent ratios in the Nation, with the average home price being $107k and the average rent being $1,416/Mo.

Does anyone have a recommendation of a national collection agency that is effective?