What boatbob said and from another vet...Viet Nam, good luck. My grandson just came home from Afgan for a couple of weeks and is heading back. Anywho, might as well give the battery to a friend to use or sell it. You could keep it hooked up to a "Battery Tender". If you don't it will die a slow death and be useless when you get home.
I also would put the car on wooden blocks to take the weight off the tires...if they are pretty new and you don't plan on changing them. Now if someone at your home can roll the car back and forth once a month or so then not needed. Irish Spring is good, dryer sheets seem to work also but both will have to be replaced as they wear out. If no pets or little kids can get in the garage put a box of poison mouse food at the inside of each tire cuzz those little bastages can and will try to climb up into your undercarriage and engine bay (dryer sheets there also)....good luck