My family stores lots of cars and boats due to seasonal use and military service. We always change the oil, tranny fluid & gear lube right before putting them away, gets all of the gunk out . Make sure all of the other fuids are topped off. Run the vehicle up to temp once to boil off any moisture which might have accumulated in the old fluids. Any needed small maintenance preformed gets performed before storage. Always put them on blocks so the tires do not get flat spots and fatigued belts, we had one blowout once from not doing this, never again. Also be sure the tires are not in direct sunlight, if there is no other choice remove, or cover them. Batteries get pulled and brought into a climate controlled area. We don't usually use battery tenders but I have a few friends that due, I'm just scared of boil over.
The big boat gets full tanks 300gals of diesel with Biobor and Sta-Bil for Diesel from West Marine.
If you put the vehicle away ready to run then when you come home your ready to go! If it is only for a week, leave the truck and rent / borrow a car. It's usually just not worth all the hassle for a few days.
Good luck in Iraq, my brother just got back from Umm-Qsar in June, thank you for your service!