You'll be money ahead to use a software/calculator built for commercial underwriting, even if you do have to drop a bit of cash on it. 

Or, if you are a real DIY, look for accounting software.

Any software?

Find out if you need to do something to prevent further damage , I'm assuming its trashed but say if its salvageable  like tapping the roof if there is a hole ( so no rain gets in ).  

Online payment software - find an online software that's inexpensive so a tenant can pay me online.

(We only did interior upgrades on one unit that moved out during the deal making; all rents have been increased)  We dropped our management company and do our own management in house using Appfolio software and their call center service for maintenance calls.  

We are only able to find this small population of properties because of the software we developed.

They stay outside all day "except when it is cold or raining".So the dilemma is what to do about fees.

JOSEPH LORENZO if you have more than a few properties, Quickbooks (with class tracking) is the software of choice.

That's what I get for being a software guy.