If you have young kids I might recommend the discovery tour, it's a bit easier on everybody (fewer stairs, not as steep). But I learned more on the hidden passages tour, it was more guided, and the experience a bit more interactive. They keep the lights off for a few minutes unless people get uncomfortable. I think overall I would recommend hidden passages, but they're both beautiful.
I decided for the Discovery Tour because I have small children, toddler age. My teenagers would have preferred the Hidden Passages though.
I've ONLY done the Discovery tour, but i would definitely recommend it. I've done it 4 times now and always bring out-of-town visitors there. It's limited assistance I know, but i hope it helped a little.
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