I don't think I wanted a secret clubhouse, but I tied all my belongings (all right, a book, a sandwich, and a stuffed animal) up in a kerchief and carried it around on my shoulder as soon as I read Calvin and Hobbes' Yukon Ho! I wanted very much to run away and ride trains.

I have always not-so-secretly wanted to do that too. Oddly, there's also a handkerchief bundle in Harvey's Hideout, so the resonant idea was there.

I really, really wish the live-action reference films from the heyday of Disney animation survived.

Yes, me too. I do believe there are dribs and drabs, but mostly there are just still photographs for Ken Burns style documentary depictions. That reminds me, have you seen The Boys?