you don't necessarily need to buy those little bungalows in Nebraska, there are other flyover state towns with prices like that, with properties that might give back a little more.
The town I went to college in (where I shouldn't have gone to college in the first place) has a true ghetto that shares its zoning district with the college downtown main strip where kids party, and it's adjacent to a 30,000 student campus - in other words, 6 of those little $20-30K bungalows plus a little repair for each in said district might net you $3-5K a month in student rentals if they're 2 or 3 BR's. Nobody wants to touch them with a ten foot pole because there are... wait for it.... black people living around there. Clearly, though, you can see what kinda ROI potential they have. I went to house parties over there, I hung out with a couple ghetto kids and dropped them off sometimes, it was fine, just white people being scared of black people. Most of the students are suburban city kids who live on the other side of the strip in crackerbox duplexes and stuff, but there are students who care to save a bit by living in the ghetto.