I know how to calculate it; the problem is that it seems like there is always a fly in the ointment that makes one property's cap rate an anomaly from the rest of the neighborhood that takes away from comparing apples to apples.For example, whether or not the landlord pays utilities can offset the cap rate.

The fly in the ointment is in the allocation of the self storage between personal and real property. 

There is also a second fly in that ointment - If the IRS smells a rent to own or land contract arrangement they will interpret that "risk of loss" (the sale) happened at signing of the documents not the passing of deed (and the cash). 

BUT, I believe a fly in the ointment could be "them remaining the PM", which doesn't seem like a good idea to me.Finding a good Property Manager is perhaps THE biggest hurdle in keeping the expenses of owning property down to optimum.

I live a few hours from the cabin, but if I happen to be there, I'll bake cookies for the next guest.Charcoal and lighter fluid for the grill, hairdryers, first aid kit with itch relief ointment for bug bites, etc., umbrellas, ponchos, spices, cooking oil, coffee, tea sugar, detergent. 

@Edward B.As I understand the rules for charitable donation deductions, there is another fly in the ointment for this strategy.  

However, a bigger fly in the ointment has emerged as I sought funding for this project:According to institutional underwriting guidelines published within the last 30 days, no lender of mobile home parks will lend:1.

There's a lot of bad apples and scam artists out there, unfortunately, that are a fly in the ointment for all the ethical investors out there.

The fly in the ointment is that I can't get a conventional condo loan/refi because of the high percentage of investment ownership.

So here is the Fly in the ointment.