/lit/ - Literature

I've always wanted to learn but I need structure and something to progress through.
Is there a book that teaches you fundamentals and how to work up step by step?

I know YouTube is useful but I would really like a book so I can bring it with me to a cabin where I don't have internet

For the amount of time you put into learning a classical language, is it actually worth it?

Ones I am considering
> Classical Greek
Pros: New Testament, Greek philosophy, Hermetic stuff, Illiad/Odyssey
Downsides: Obviously doesn't have anything modern. Relatively difficult to learn
> Latin
Pros: Easier to Learn. Lots of medieval and Roman works. Some relatively modern works (Spinoza, etc.)
Cons: Much of Roman literature is based off Greek stuff in the first place.
> Sanskrit
Pros: Much different cultural background from western classical languages.
Cons: Probably the hardest of the languages mentioned. More niche texts that might not be interesting to the average reader.
> Classical Chinese
Pros: Similar to Sanskrit, lots of texts still left untranslated. Lots of things you would have never come into contact with if you hadn't learned the language.
> Cons: Lots of memorization of characters. Might need to learn Mandarin first in order to use many of the best resources.

Does anyone have any input on the matter? Is it even worth it to learn a language like these in my spare time? Will I end up putting 1000 hours in and not even be able to read anything of note?
Would I spend my time better just reading translated texts from all of the aforementioned languages but being able to split my time up better?