Owners of the 10 new Resort at Paws Up Wilderness Estates (www.pawsup.com) in Greenough, Mont., can navigate the 37,000-acre property without polluting the Big Sky. Each of the 3,248-square-foot timber vacation homes comes with a Miles Electric Vehicle, a low-speed car that can be charged on a 110-volt wall socket. The houses, priced from $1.675 million to $1.875 million, also feature professional-grade kitchens, great rooms with vaulted ceilings, and lofted game rooms, and all come fully furnished—including linens, china, and artwork. Homeowners can avail themselves of the Resort at Paws Up’s activities and facilities, including horseback riding, fly-fishing, and a full spa. Owners can also make their homes—and their electric cars—available for rent through the resort.