Pop is situated half way between two Publix - the one on west 192 near Black Lake Road (Orange Lake Town Center store) and the one on the 192 east at the junction with Apopka-Vineland Road (Poinciana Place store). You'd have to drive past Pop to get to the first one, so that's not going to be the best bet for a stop-off on the way from the airport.
The 417 Central Florida Greeneway is by far the best route from MCO (is that where you'll be flying into?). If so, you'll need to exit at junction 6 and follow the signs for 535 south. This is a
huge junction and can be a bit difficult to navigate if you haven't done it before. As you travel south on the 535, Publix will be on your left just before you hit the 192. To reach Pop once you're done, you'll have to travel back up the 535 for a few hundred yards before joining the Osceola Parkway travelling west (where you'll need to pay a toll to join). You'll cross the 417, followed by I-Drive South (with Gaylord Palms on your left), then the I-4 before passing through the "Welcome to Walt Disney World" arch

yay: ) and then Pop will be on your right.
However, a better bet in my opinion (and the option we'll be using in November) is either Albertsons on South Orange Blossom Trail (just north of exit 11 on the 417) or Publix on South John Young Parkway (just south of exit 10). Either way it's just a hop on and off the 417 and then you simply take that as far as exit 3 directly onto the Osceola Parkway travelling west to Pop. That way you'll avoid both the potential for being bamboozled by exit 6 and the toll on the OP (as you join it further west and closer to Pop).
ETA: Here are the zips for the ones I've mentioned:
Publix, Orange Lake Town Center- 34747-8210
Publix, Poinciana Place - 34746-5505
Publix, S John Young Parkway - 34746-6543
Albertsons, S Orange Blossom Trail - 32837