Kudos on the rsa mixing analogy. A great find.
The zkp mostly depends on an operation of some sort, with the verifying party being able to dictate some terms that the opposing party can use. Of course this is very dependent on the question being asked in the first place.
The peggy victor secret door combination wouldn't work if the question was phrased as Victor wanting to know if Peggy could get to the left/right side of the tunnel as opposed to knowing the password to get through the door.
So the question in real life is could possibly be summarised for kids as so:
I would like to know if you understand how A/B/C works, or that you are privy to a knowledge that says that you do. The proof of which might be some form of test, which possibly could translate into some form of verbatim exposition of the accepted answer, or a physical expression of the knowledge ( i.e. do you know how the combustion engine works, and yes, here's the flat 8 with twin carbs that i made with my bare hands with the steel hewn from the depths of a mine somewhere in the northern reaches of russia ). The tricky thing with ZKP, and this extends to a lot of other areas, is whether upon producing the proof, it in itself reveals the manner in which to derive the answer.
And it appears in real life, that translates into the amount of time necessary for the verifying party to reverse engineer the proof to determine the machinations inside. So i contend that ZKP is also about increasing this time to a proportion where it does not make sense to figure this out.
And with that you'd be able to apply this to quite a number of real world examples.