I have the 2 units already done with separate entrance (utilities are not separate). 

My average turnover vacancy is less than 15 days, so I lose half a month of rent and utilities.

I have been utilizing Facebook MTR groups in my market as well and have come up flat.Like I originally stated in my post I am currently breaking even simply with my in season short term rentals, which has been covering my annual expenses.

Taxes, insurance, pest control, utilities, software, etc comes out to around $13k per year each for my 2 bedroom cabins.Also unplanned capital expenses will add up.  

They continue to roll over until they can be fully utilized, either by offsetting future rental income or when certain events occur (e.g., your income drops below the threshold or you sell the property).If you sell the property, the accumulated passive losses are released.

Both of these cost you (from rent) utilities, amenities supplies like paper towels, and furniture deterioration.

My question is, whats the HVAC system to use that provides separate utilities, and separate control per unit. 

SFH are easy to manage, you can have the tenants take care of utilities, lawn care and snow removal.   

We don't utilize any arbitrage method...I am not sure there would be a huge spread like there can be for short-term rentals.   

Raising the rents, billing back utilities and growing the gross income on the park are all your future opportunities and for you to capitalize on.