Time to feel the force! Star Wars Weekends have plenty to choose from, so I'll try to list many of the things you can do with your son.
- Afternoon parade features many Star Wars characters and celebrities
- Jedi training for kids throughout the day (they get to battle Darth Vadar or Darth Maul!)
- Many Star Wars characters wandering around all day
- Trivia contests for both kids and adults
- Celebrity autographs (you will need a fast-pass to meet the celebrity)
- Special merchandise for sale
- Mickey is dressed as Jedi Mickey for a meet and greet
Of course, things do change year to year, so I would keep checking this
link for more details. As for meeting Darth Vadar, he will be available on and off at a designated spot during the scheduled time. Just wander over to the area and get in line. He should be there most of the time, but he will need a few breaks from the summer heat. To think he thought he rule the rule the galaxy!