Hi, Jill!
Welcome back to the Disney Parks Moms Panel, and thanks for visiting us with your question.
My honest opinion is that it would be best to see World of Color and Fantasmic! on separate nights to truly enjoy the experience of both. World of Color is a 28-minute show, so it would be about 10:15 before you could even begin to make your way out of the Paradise Bay area, along with hundreds of other Guests. You’d still need time to walk across the esplanade, enter Disneyland Park, and make your way to the Rivers of America. That is also a popular time for many Guests to leave Disney California Adventure Park and enter Disneyland Park, so I can guarantee you would experience at least a small delay at the turnstiles as you enter.
In my experience, even if it’s not peak season, it would be very difficult to be seated by 10:30 when Fantasmic! begins if you were coming straight from World of Color. That said, they are phenomenal shows, so I do strongly encourage you to see both if you can—but preferably on different nights or with a bit more time between show times.
I hope this helps, Jill. Please don’t hesitate to ask me more questions as your planning continues!
Wishing you magic,
Courtney