looks like a place to hide a chest full of money..

All great insights already here Winn, but if you are able to oversee the painting, there are some ways to help with this often unavoidable turn over expense....For example, this time insist on some high end paint (think specialty paint store or the very best big box stuff); try a pearl or washable finish; I like one color for all the interior of all my units, ideally a white that can hide some imperfections (know and keep the code); this means no color or matching mystery later; then on the next turn over, see if you can't get away with just a wall cleaning; use a damp sponge mop with tsp or a tsp substitute  (and then rinse it with a clean water and a damp sponge mop)..not too much water, just damp.. 

Unless you are trying to hide the neighbors mess, I wouldn't install a fence.

There is nothing to hide as the screening process a landlord sets is extremely subjective.

If they are unwilling to show you the bank statements they are obviously hiding something. 

You know she has received some mail there and you are onsite for a reno so no reason to hide your  interest.  

They are not allowed to poke holes in the walls to hide their TV wires, and you aren't going to do it.  

What if he is trying to hide a criminal background?

Extra addresses could be an attempt to hide something.

Just because a tenant wants to pay upfront doesn't mean it's a scam or they're hiding something.