Other translators may have different ideas — particularly with Sindarin, which is not my expertise — so stick around to see what they have to say! Here are my takes:
“For where am I to go? And by what shall I steer? What is to be my quest?”
Q. An manna menuvan? Ar manen hiruvan i tie? Mana cestalenya?
[lit. “For where will I go? And how will I find the path? What (is) my quest?”]
S. An navan menin? A naman hirin i ven? Man i gestad nín?
[lit. “For where do I go? And how do I find the way? What (is) my quest?”]
“I’m going on an adventure.”
Q. Mínanyë veryandenna.
[lit. “I’m going toward adventure” = “I have adventure in view, I’m making for adventure”]
S. Menin na verthas.
[lit. “I go to adventure.” — credit to Elaran for this phrasing!]
“Well, I’m back.”
Q. Mai, nanwénien.
[lit. “Well, I’ve come back.”]
S. Mae, dandúlen.
[lit. “Well, I’ve come back.”]
We don’t really know the Elvish equivalent of the English interjection “well” acknowledging a situation or introducing a statement, so I’ve taken a leaf from the Romance languages and used the adverb “well” (Q. mai, S. mae); compare Spanish bueno, French bien, Italian beh (< bene), etc. Other options abound.
“The last pages are for you.”
Q. Tyéna i telde lassi.
[lit. “For you (are) the last leaves.”]
S. Echin i lais vedui.
[lit. “For you (are) the leaves last.”]
There are neologisms Q. parmalas / S. parlas (lit. “book-leaf”) for “page,” but I think simple “leaf” works well on its own.
