A quick Google didn’t yield any definitive answers. Disneyland wasn’t built with the super tunnel system that Walt Disney World has (which apparently will protect you during a nuclear attack). Also WDW may have a bona fide shelter under the Main Street Train Station.
This speaks, I think, to the illusion that Disneyland is not only the happiest place on earth, but also the safest. As we walk through the entry tunnels, we are greeted with a sign that reads, “Here you leave the world of today and enter the world of yesterday, tomorrow, and fantasy.” This hyperrealistic constructed world claims to take us out of time, away from real world worries. There are reported cases (see any of David Koenig’s books) of people getting so caught up in the illusion that they do something reckless, and thanks to Disney’s PR and law teams, any injury is quickly covered up. Koenig also writes about violent acts at Disneyland, easily occurring because people lower their guard at Disneyland. It’s a safe place.
So why not extend this illusion to nuclear attack? No one wants to go to Disneyland and think about nuclear bombs. In Tomorrowland, there used to be attractions celebrating nuclear energy used to make life easier, not destructive.
I’ve decided that the safest place at Disneyland, in the event of nuclear attack, is the Haunted Mansion. The stretching room is actually an elevator that takes you underground and the hallway to the Doom Buggies takes you outside the berm. Perfect place. And the Grim Grinning Ghosts are good company. Why not Pirates of the Caribbean? It’s also underground. Simple answer. The water, that recognizably smelly water, will become radiated. If there’s a secret room down there (the room where Walt’s body isn’t), maybe that’s the safest, but it doesn’t have the capacity.