Hi Angie!
I know from experience that traveling with grand-kids is one of the BEST ways to experience the Walt Disney World Resort. You can absolutely utilize the
rider switch option just as you described. However, not every attraction provides the rider switch option.
Here is an attraction list that allows rider switch to help with your planing:
Magic Kingdom Park
Big Thunder Mountain Railroad
Splash Mountain
The Barnstormer
Space Mountain
Stitch’s Great Escape
Tomorrowland Indy Speedway
Epcot
Mission: SPACE
Soarin'
Test Track
Disney’s Hollywood Studios
Rock ’n’ Roller Coaster Starring Aerosmith
Star Tours® - The Adventures Continue
Twilight Zone Tower of Terror
Disney’s Animal Kingdom Park
DINOSAUR
Expedition Everest - Legend of the Forbidden Mountain®
Kali River Rapids
Primeval Whirl
Have a great time with your grand kids!
Anne