Usually (but not always) if you buy in a C neighborhood, you will get C or lower tenants. 

A multi-family is going to auction in a few weeks in a desirable neighborhood, but can be cancelled beforehand.

To be direct, my business model isn't to target the $30k houses, and where I invest (in the Twin Cities), anything in that price point would be in pretty rough neighborhoods. 

Tell them you are thinking of buying in the neighborhood. 

From my neighborhood, I can walk to a starbucks, a cuban restaurant, a bar with a good pool table, a good mexican restaurant, pizza shop.

We have never had such trouble with tenants and neighborhood as you describe! 

One metric that I look at is the ARV compared to the neighborhood values.

The crime rate there is low compared to downtown Chattanooga, but I'm not sure if Red Bank is an up-and-coming neighborhood, an established neighborhood, or a place people are fleeing.

Also, recent newspaper articles have stated the fact that FHA approved condominiums can and are losing their approval if the units in the Condo are being used for short term rentals.The short term market is growing and inventory is diminishing but before diving in do your due diligence. 

The neighborhood will really dictate what you can get, both as a purchase and rent.