Hi Kate,
Your trip will be here before you know it! Sounds like you are looking for some action characters during your trip.
The Power Rangers are no longer appearing anywhere at Disney World. They made their last appearance at Disney's Hollywood Studios (DHS) in August of 2010.
Your best bet to find Stormtroopers is to head to DHS and where you might encounter them at
Star Tours.
A couple of Stormtroopers usually appear on stage with Darth Vader during
Star Wars: Jedi Training Academy. They may also appear before or after for pictures with Darth Vader.
Be sure to check the
Times Guide at DHS for character location and appearance times.
Times Guides are available at the entrance of the parks, Guest Relations & most merchandise locations. If you don't see the Stormtroopers listed, check with Guest Relations. They can call the Character Hotline and check for you.
Wishing you many magical memories :-) Allison