Sta-bil, full tank of gas, and a Battery Tender.
When it comes time to start the car again, I just turn the key to ON for a couple seconds to let the fuel system prime, then it starts like I drove it the day before.
Flatspotting isn't an issue, the tire s even out after jsut a little driving. Hell, the snow tires on my BRZ flatspot while I'm at work. From what I understand, some tires use nylon belts that don't like the cold (not sure why they're used on snow tires, but ehh).