Unless you are unknowingly renting far below market value or can do something to dramatically increase rent (highly unlikely, and even if so, you have a huge gap to makeup $500+), I would get rid of the property as fast as I could. 

I would use a fast dry oil primer like PPG's 17-964 (http://www.ppgpaints.com/products/seal-grip-interior-premium-quick-dry-primer-sealer) to seal up the paneling.  

No, they need it to conform at closing so the bank can sell it fast. 

You'll be amazed at how fast your network increases.

If it was a new purchase I would simply post and mail as there would be no existing landlord tenant relationship or past practice.All you want to do is get rid of them the fasted and easiest way possible.

The good thing about real estate is that it doesn't move fast.

Cap ex adds up fast.

I work with some investors whose goal is to pay the buildings off as fast as possible and maybe some of that just rubbed off on me too, but now I'm looking at the long term. 

Is their monthly coaching calls; can I text or email questions and expect a response fast; can you review my marketing; scripts; or systems and provide feedback?.

20 days to closing will usually be sufficient; as stated by others above, the banks can't even close that fast sometimes.Proof of funds is important, as mentioned by others as well.What hasn't been mentioned is being in position to get access to the "pocket listings" / "office listings" AKA "exclusive listings".