They're very motivational.

I have them under separate LLCs with individual accounts as of now because they are all unique properties that are also kind of businesses.

Let me help you out with a competitive bridge product.

There's no real 'fair' way to truly separately meter the natural gas used for the different units, unless you get into rabbit hole land of re-inventing a wheel and a series of sensors measuring heat and air flow within separate ducts, on your (customer) side.I'll comment on each option individually and your decision will be numbers driven. 

There are a number of short term interest only products that will only cover the purchase price but those rates are typically still going to be a bit high 

You could have 4 individual little cabins... if they're all on one lot and all platted on the same parcel/strap ID then it's residential.

Callrail seams like a really good product but it's $30 a month for 500 minutes or $120 for 2000 minutes.

We don't charge a fee if renter renews so we are setup that we have no motivation to put a bad renter in and late fees we split .

They also report the individual to a credit reporting agency so it sits on their credit and hopefully stops them from scamming the next person.

At this point in my life I am fully motivated and ready to jump in with both feet.