the fuel is probably contaminated by now, most gasoline has a shelf life of 3-4 months if left untreated...you're certainly going to experience a rough time until you're through 1-2 gas tanks. throw a healthy amount of drygas or stp fuel treatment (red bottle) into the gas tank to absorb any moisture in there.
the oil should be changed as well since moisture (water) and oil are bad mixers. I would change the oil before attempting to start the car. the battery if original from '03 is probably toast now anyways, a new battery is not only a good idea, it's probably time for one anyways.
the belts should be checked for rot and cracks, if they are showing signs of either, replace them. the same goes for the tires but odds are that they are ok depending on where the car was parked. you mention that it was covered, this keeps UV and ozone away from the rubber so they are probably still good. check their pressure and adjust as needed...you'll obviously have a large flat spot on each tire but they should work themselves out during your drive home.
I used to store my cars for periods of up to 9 months at a time when I used to travel to Africa for business, I've been through it all.