You don't need to jack the car up, modern tires will not flatten if left sitting for a few months. Just over inflate them by 5-10lbs and let the car sit. (I store my Vette for months over the winter, no flat spots)
You can also put some silica gel packets in the car in plastic containers without lids to keep the interior dry.

You should put some stabil in the gas tank and hen take the car for a ride to get the stabil into the engine, then refill the tank to full will 91 octane.

You should also NOT just start the car every now and then and let it run. Unless you can take it for a ride and let the entire power train warm up and get the oil hot enough to boil out the water etc, just let it sit.

What's the purpose of the styrofoam?

__________________
You have your way. I have my way. As for the right way, the correct way, and the only way, it does not exist.