In the lending realm, the line is drawn between the 4th and 5th units.

Your first line of defense against loss is going to be insurance on the property, then an umbrella or excess-lines policy on the company. 

At $500 a month rents before expenses in the D-Class space, combined with Owner Financing, and the need to rehab 41 of the 60 Units, and being in a small town of less than 1,600 people, the only thing good that will come out of this deal is that you'll rehab his remaining 41 units for him then somewhere along the line realize you'll never make any money on this deal.   

Not saying it's not possible, but this is likely the hangup. buying cash and then cash-out refi is easy and done all day, even with commercial loans, but likely all will want you to carry some liability in some form (skin in the game) that said, I'm just one lender I can't speak for all of them  Ira or solo 401k are not allow to have recourse loans this is a tough loan product..

Your business entity should own nothing but a check book, land line, business cards and the other 14 requirements to avoid having the corporate veil pierced when a lawsuit comes. 

It depends on your climate, you might do an energy audit or just switch to electric, it doesn't seem too out of line for four units though $35 ish dollars per month depending on the size of the unit and how much they use the climate control.

I know we live in the day where you can just find on line more and more of the information you used to get from  a good realtor. 

That should be a discrete cost line item and factored into the ROI, as most of these costs will be capitalized I imagine.

There are some very reasonably priced laminate and vinyl products out there (there are also some crazy expensive options that are pretty sweet). 

Once it is established that real estate is Abandoned as a matter of law, -there can be no trespass because no one is claiming an interest that can be trespassed against.While trespass against the owner of record could be part of an Adverse Possession claim (as in fence line disputes) where the owner had no intent to abandon his/her interest in their Real Property.