Satzman, Unfortunately, this time of year comes all too soon
You found a safe spot to rest your car, great. I agreee with the comments of Tahoe Healey for the most part. I'd add a few:
-Place a plastic sheet underneath the car. depending on the moisture coming through the floor where your car is stored, the plasic sheet can help prevent your car from absorbing more moisture than necessary.
-check and top off all fluids.
-take all unnecesary items out of the car such as tools, cloths, boots/tonneau covers to prevent moistue accumulation/mildew.
-Put the top up.
-Remove the battery from the car and store it in a cool dry place - not on a concrete floor. Use a trickle charger once a month or so to insure it's charge.
-I have a set of old wheels I put on the car when I store mine. It prevents the "flat spots" from occuring and gives me time to clean up the "good wheels" for spring. Some people jack up their car and place it on jack stands to keep the wieght off the springs and tires.
-Don't start the car every week or month, let it "sleep". I know there are varying opinions on this, but think about it. It takes 10 - 15 mins or so of driving to heat up the engine and exhaust system. If you don't fully heat everything up, you'll envite condensation into your exhaust system and accelerate rust.
-Lastly, I'd cover the car. Dust and dirt flying around, even on a "quiet building" can get everywhere.
You may find a few more, or differing suggestions.
Any projects or things you can work on while your car is laid up?
Here in Ohio, I have a month or two before I have to do the same thing, and I'm not looking forward to it.