From the airport to the RPR, you still want to visit the Publix just north of the parks. Driving from the airport to the resort is all done on highways. As you exit the airport, you'll be on the 528 heading west towards I-4. You take I-4 north to Kirkman Road (get in left lane), and go north. From there you'll pass the parking garages and the offsite hotels. The Publix is a mile north at Conroy road. So there's really no stop on the way from the airport, it's best to visit the places near the resort.
A good idea is to bring up maps.yahoo.com, get directions, put MCO in the start box, and put the Publix address as the destination.
4606 S Kirkman Road
Orlando FL 32811
The directions on the map site are different. You still end up on Kirkman road, but you don't need to make the u-turn it talks about. Just turn left at Conroy Road and the Publix is on the right side.