Setting up a sleeping area in barn and considering the installation of ductless heat pump

I own and operate a small stable, which is located nearly fifty miles from my home.

I stable a half dozen horses and need to feed and care for them everyday.

The drive gets super exhausting and aggravating. My goal is to set up a small apartment within the barn, where I could stay a few nights a week. It could be very simple, with little more than a bed, refrigerator, toilet and sink. I would also need some type of temperature control. The weather in the local area is often severe. In the winter, it isn’t unusual for the temperature to drop below freezing for weeks at a time. During the summer, we deal with excessive humidity and temperatures in the upper eighties. There is no insulation in the barn and very little ventilation. Because there is access to electricity, I have considered making do with a portable air conditioner and a space heater. This solution wouldn’t cost much or require professional installation, but wouldn’t suffice during severe weather. Since I hate driving on snowy roads, during blizzard conditions, I’d prefer a more powerful heating system. I am currently leaning toward a ductless heat pump, which would provide both heating and cooling capacity. The heat pump would take up very little space, run quite efficiently, and combat any weather. However, I’d need to hire an HVAC contractor to handle the installation, and the unit comes with a hefty price. A benefit of the ductless heat pump is that it could heat up or cool down the space very quickly. I would only operate it while I’m on the premises, which would keep the running costs very low.
Air vent