Hi there Katrina!
Wow, it will be his first visit at 19. Sounds like he's going to really enjoy himself! I've made a list of our family's favorite rides and shows below as an easy guide. If he enjoys thrill rides then I have to say he has to check out Everest and Rock-n-Roller Coaster. When you arrive, please make sure to check the Park Times Guide for character appearance locations, parade, and show times. Times Guides are available at the Park Entrance, Guest Relations, and most merchandise locations. I hope this helps with your planning. I hope you and your family have a Magical Time at the Walt Disney World Resort! If you have more questions, we are always here to help! Thanks so much for asking the Moms Panel!
Magic Kingdom...
Buzz Lightyear's Space Ranger Spin, Haunted Mansion, It's a Small World (for nostalgia), and Pirates of the Caribbean, Space, Big Thunder and Splash Mountains, PhilharMagic
Don't miss: Both Parades, Wishes Fireworks, and catch a Dream Along With Mickey Show!
Hollywood Studios...
Muppet Vision 3D movie, Toy Story Mania!, Rock-n-Roller Coaster, Twilight Zone Tower of Terror, Shows: Indiana Jones Stunt Spectacular; Lights, Motors, Action! Extreme Stunt Show, Beauty and the Beast
Don't miss: Fantasmic!
Epcot...
Soarin', The Seas with Nemo and Friends (specially Turtle Talk with Crush), Test Track, Spaceship Earth, Innoventions, Journey into Imagination with Figment (nostalgia), and World Showcase
Don't miss: Illuminations: Refections of Earth
Animal Kingdom...
Kilimanjaro Safari, Kali River Rapids, Maharajah Jungle Trek, Pangani Forest Exploration Trail, Triceratops Spin, Dinosaur the ride, and Everest!
Shows: Festival of the Lion King, Finding Nemo - The Musical