I would steer clear unless you are able to purchase both sides so you have complete control of the property.

You are creating value and since you're the one creating it, you have a lot of control.

Always control what you are responsible for until other people can be trusted.  

Am I a control freak?

Since they are on rent control, they still need a 1 year lease , right?  

"I hope you're bringing a licensed contractor that knows anything like I do about Mildew and mold control.

Stay in control of things you are responsible for.  

@Aaron Lovett  logging in most states is controlled by the STATE forestry division counties have tree ordinances but not logging rules etc...

The deal with them is a flat fee of 100.00 total to list on the MLS and they list it with all the FSBO sites and I use my own number with them so all prospective buyers have to call me to give them lockbox codes so I have full control of the listing. 

Good luck on the investigation,, as far as running any type of drainage.. we were cautioned at our property when we put the sump pump discharge hose to the front yard so water would drain into street and go down into the sewer grate.. we were told by city we couldn't do that and they suggested we put in a underground tank reservoir type thing.. basically all we did then was move the discharge hose to further point in back yard.. it was a flip house so we only had one season to deal with the issue.So don't do all the digging work and then find out you can't revert the water to the street and have to yank it all out.. if you do a drain tile type thing to edge of front property line.. water is funny you want to control where it goes but it has a mind of its own sometimes.