There was a secret tunnel from the Fort on Tom Sawyer Island to Sleeping Beauty Castle. Back in the early 1960's, my friend and I got to use it as it was night and we missed the last raft. The soldiers unlocked a door on the north wall of the fort and we walked underground all the way to the Castle exiting by the Sleeping Beauty walk-thru. What was interesting was that this tunnel was just like the others on Tom Sawyer Island. That was way cool. I suppose the tunnel is still there but the Fort is closed now.
Been going to Disneyland for over 50 years. Walt Disney must have been one of the best people of the 20th century.