I've had properties in pretty rough neighborhoods and i've never had this issue.

Working in a busy property management company, I'm often asked for advice on camera and alarm systems, and in rougher neighborhoods sometimes it can be a toss-up on whether to keep a property boarded-up between showings. 

Quote from @Matt Gravil: Monthly rent totals $20,038@Matt Gravil So, at an average rent of ~ $800/property, I'm assuming these are in C/D neighborhoods?

Does anyone recommend knowledge sources on building a mobile home parks (websites, books, organizations, plans, etc..). 

Can try to reposition to Class B, but neighborhood may impede these efforts.Vacancy Est: Historically 10%, but 15-20% should be used to also cover tenant nonpayment, eviction costs & damages.Tenant Pool: majority will have FICO scores of 560-620 (approaching 22% probability of default), many blemishes, but should have no evictions in last 2 years.

Some clients who are more aggressive will invest in B-/C+/C class areas in Dayton 1-4 units and get A LOT of cash flow, but incur risks of evictions, expensive turnover renovations, and general C class neighborhood headaches.What are you looking to achieve?

Going more west and south especially after 42nd st really changes the neighborhood. 

Can try to reposition to Class B, but neighborhood may impede these efforts.Vacancy Est: Historically 10%, but 15-20% should be used to also cover tenant nonpayment, eviction costs & damages.Tenant Pool: majority will have FICO scores of 560-620 (approaching 22% probability of default), many blemishes, but should have no evictions in last 2 years.

We would love to work together with a organization that sells the property and has services like rehab network, financing, property management. 

You can still find single-family homes in the $80k–$100k range and duplexes in the $130k–$150k range, even in C and C+ neighborhoods that are seeing steady improvements.