What is it zoned as, and how easy would it be to redevelop into another use?

If its on an arterial or in a LR zone or urban village,  probably not.   

If you find high vacancy, that is a red flag for the market and you should be cautious.

If it were mostly rock I think I would be fine with it but the crumbling sent up a red flag for me.

You gotta get outta the comfort zone and bonk contractors heads to get the projects done. 

Welcome @Daniel Sanchez - my 3 non-negotiables would be to familiarize yourself with your credit score and the things you can do to improve it, figure out how much money you will need upfront so you can be prepared, and identify a target zone or zones in which to buy. 

Talk to your town first to see if you can legally convert to a duplex, zoning department.   

HE insurance will not cover floods and since we are not in a flood zone (on a hill) we did not add flood insurance, but it will cover some things (overflow from our backed-up sump pumps and a roof).

Understandably, they are built on a trailer platform (which might be a zoning issue in your location).

For example, often fire damage is water damage--they put the red stuff out with wet stuff.