Indoor sprinklers are so effective. 

Just a one week shortage will cause a price ripple that will last for months going into building season.  

Heating costs go up in winter, as does electricity due to the reduced natural light and more people indoors.

Glazing in walls, enclosures or fences containing or facing hot tubs, spas, whirlpools, saunas, steam rooms, bathtubs, showers and indoor or outdoor swimming pools where the bottom exposed edge of the glazing is less than 60 inches (1524 mm) measured vertically above any standing or walking surface shall be considered to be a hazardous location.

When I purchased my property, I had read all the exciting developments in the works...indoor waterpark, shops, new hotels, restaurants, etc., but was severely disappointed when I went recently with my family. 

Offer to buy them a few indoor portable heaters until you find a solution. 

Quote from @Jay Hinrichs: Quote from @Chris Mason: Indoor shopping malls as they existed in the 1990s are dying, but retail is not.

I plan on converting the barn into another sleeping space and indoor/outdoor rec room.

.- multiple indoor common areas (think 2 separate tv setups). - exterior "usable square footage" (think covered patio, pergolas).- extra storage space so tenants don't feel the need to squeeze their entire lives into one room (extra garage space, attic, detached shed)- room for 2 full refrigerators!

Some Instagrammable indoor-outdoor carpet, chairs, and umbrellas, and you can take it up a notch for less money.