For 2k a unit (32k total) I can upgrade my electrical in the units to adequately provide service to Air conditioners and electrical conversion to hot water heaters.

@Daniel Weber @Jordan Williamson Thanks for your help!

@Jordan Page @Michael Noto @Greg Scott @Anthony GaydenGreat feedback.

You can also add air conditioning now or later relatively easily. if you want to add hot water baseboard the boiler pipes and time to install will cost you. if you want to do electric baseboard you might have to do service upgrade to support the additional circuits and amps they draw. 

I am also an Air Force vet, and I am currently working on a master of science in Mechanical engineering. 

@Amanda Webb I can't speak to the regulations but if the primary motivation is ROI it probably isn't worth it you can get better returns elsewhere, if you want to use the cabin part of the time then I would continue the search and understand that it will be an Air BnB subsidized vacation home and not an investment.

The funny thing is there are usually many cranes in the air downtown.

Running a vent for central air is not a problem, but you will likely need a return air as well.

Option 1: pay around 20K to install new HVAC/minisplit system.Option 2:  pay for heating and cooling as a service which is about $350 a month without installation fees for 10 year contract, they do all needed repairs and service a year included, write it off as a service. when I sell pass the cost/contract off to the next buyer. details at: https://www.knochelmann.com/advantage-program/heating-air-conditioningHas anyone had anyone used something like option 2 and what are your opinions?

I have been running the rental calc over and over again on different properties and I am not getting the return that every expert talks about.My next game plan is looking for SFR that may have an in-law suite or full basement to even Air BNB