The duplex has been treating me well with good cashflow.

I know I can't write off the lost income, i.e. if it'd rent for $2,000 a month, and I donate the use of it to the church, I can't write of the $2,000 as a charitable gift.I know if I just treat it as a 2nd home, I can write off the mortgage interest and property taxes, but how do I set it up so I can write off the entire mortgage, insurance, utilities, etc?  

There are two schools of thought about treating reserves as expenses.

Most of all, whatever you do just treat it like a business, not a hobby.  

They are on the corner of Treat and Main Street, above US Bank.

I know its treated me well all these years and has led me to some pretty incredible financial adventures that wholesaling simply could not do.But if I lived in some of the rust belt markets or other markets were there are literally more homes than people to put in them. .I equate that as nothing more than being a used car salesmen.. price points are the same. style is the same.. once your done your done.Where real estate gets good is 10 to 15 years into it ALL of your business should come from referrals.. this simply will not happen in wholesaling.. wholesaling your just as good as the last sucker you talked into selling their house to you undermarket  :)

It can create the perception that you have excess money.I treat my tenants with respect, but I would never even consider mailing a birthday card.

Then treat him as you would any person you would do business with.  

Because tax law treats investment and owner occupied property differently, I would imagine that the only consequences would be in capital gains and depreciation changes.

Frequent inspections, perimeter spray all units, and treat each occurrence asap.