Bought a nightmare property- could use some help

[Ryan Smith]

Nightmare story,
I've bought many homes before but this was by far the worst ever. 
I just bought a seller financed property in Dunn from a person that I previously trusted. I definitely should have done my due diligence before. Upon having to evict the tenant, I noticed that the plumbing was backed up and still cast iron. I thought to myself, no big deal it's only a few thousand more to get my plumber in there to replace it, but once my once my contractor got in to fix the floors (which were buckling) he saw a cyclone of termites. And an infestation of German roaches that made the pest guy jump (he said).

After everything was said and done, we incurred 4 times the cost as I was told/ estimated. I definitely should have followed my first rule, get a $50 inspection.

Has anyone ever encountered this? What's the worst thing you've seen?

Should I sell it to a cash offer company?