The metaphors of camel, lion and child have nothing to do with finding joy, experiencing life, or whatever that could matter in the context of this posting, and Joseph Campbell is pretty weak resource on Nietzsche.
No, it has everything to do with it all - particularly becoming a child again, rather than living via your children, who will eventually no longer be children and then leave you.
As for campbell, he studied him plenty and even curated a "portable jung" compendium. Moreover, his description of the camel, lion, child (from, at the very least, Zarathustra) is exceedingly accurate.
Quite funny from someone suggesting that being very into Jungian thought gives you some credibility when it comes down to Nietzsche.
> particularly becoming a child again, rather than living via your children, who will eventually no longer be children and then leave you.
Please, just go and read the original. It should make it clear for you. For now your "interpretation" of Nietzsche is equivalent to New Age take on Buddhism.
Nietzsche's ideas where not for producing self-help advice on having hobbies.