As PP mentioned, Launch Bay is an area you can walk through, and depending on what you are interested could take you a five minutes or an hour. If you want to see the film, check out the memorabilia, and get in line to do autographs then it will take time, or you could just walk through and check it out quickly. As for the rest of the park, you can spend a day there easily doing the rides and shows, and seeing the nighttime events. Backlot Tour is closed and Lights, Motor, Action show is closing in April, but you have:
Rides -
Toy Story Midway Mania (fun for all ages)
Rock N Roll Coaster
Tower of Terror
Star Tours(Star Wars themed 3-D simulator)
Great Movie Ride
Shows -
Indiana Jones Stunt Show
Beauty and the Beast
Voyage of the Little Mermaid
Disney Junior Stage show
Muppets(3D movie)
Nighttime -
Fantasmic!
Star Wars Fireworks
cassie58