Need help vetting this before I pull the trigger

[Dori Arazi]

This would be my first time trying to do an all cash rehab refi and hold. So needless to say I'm pretty nervous. 

This property in Nashville, zip 37216.

Original property was a 2 br 1 bath duplex and an additional expansion of 1br 1 bath was added. 

They are presenting it as a "tear down" or "as is" deal. The property is extremely distressed. Full on, war-zone meets hoarders, but in a rather desirable neighborhood. 

They are asking $314,000. Land value of that lot is $170-220. I am offering 200k, hoping to get it between that and 215k. 

They are asking to negotiate an offer before even seeing it. Just base don pictures alone, I am estimating around $50K in rehab. 

Assessed value of a triplex in that area is around $320-340 (no triplexs actually exist in that neighborhood, these are averaged comps). 

Rents for a full reno in that neighborhood are:

- 2br : $1350-$1500

- 1br: $850-$1070

I figure if I get it for $210k + $50k reno = $260 all in. Hope to assess at $330k. Can pull a 75% loan against equity at $247.5.

So if all goes well I'm in this deal with a $247K mortgage plus ~$15K cash. 

Grossing an average of : $3700 mo

Anything I can/should be doing do additionally vet this deal?

Thanks!