FYI, roof leak, a couple of broken windows, partially collapsing porch, open foundation and damaged steps.

The long-term corporate above I mentioned was a short term rental with another management firm until a tenant did $60,000 worth of damage to it during spring training.

If you make even the smallest mistake in your paperwork, the courts can slam you with triple damages awarded to the tenant.  

If there is a leak, they will discover it quickly and prevent too much damage. 

I am going to offer $300k on the basis that she has no Realtor fees, it needs new windows, and the basement apartment needs a rebuild (last tenant was an elderly lady/hoarder, no major damage, just filthy and needs new floors).My thought is that I offer a 30 year amortization at 5% with a balloon at 10 years.

Property damage.

Secure your property from further damage as you are required to mitigate damages. 

Once you get the keys, inspect the property and return the balance of his deposit (after any damages or outstanding rent has been deducted).

Better off with a vacant property than one with a terrible tenant.Also, doing periodic inspections is a good idea once you have somebody placed to make sure the property is being maintained and not damaged. 

Ask them to go back daily and check on the pipe situation to make sure there isn't any further damage.