I am currently watching this Korean drama, A Korean Odyssey (화유기), on Netflix. I found the Hanja of the movie title: 和遊記.
Other than English, I also speak Chinese as a first language, so I mostly know 西遊記 and mythical/fantastic creatures in Chinese. Aside from Putonghua, the national spoken language of China, I have some knowledge of my hometown dialect and some knowledge of sound shifts in the Chinese language.
I once learned Hangul, simply because I was interested in the linguistic side, and to some extent, I learned some basic Korean words.
With knowledge of the Chinese language, sound shifts of the Chinese language, Chinese folklore, Journey to the West in Chinese, Hangul, and some basic Korean words, I could parse some dialogue at a very superficial level, like "Thank you" and "Hello" in Korean and maybe some loanwords and some topic-comment structure.
In this TV series, I am wondering how the names are derived.
和遊記 - This is probably a creative name. 遊記 has the Hangul 유기, likely derived from the Middle Chinese pronunciation. But I am aware that South Koreans nowadays may take the Pinyin's pronunciation and put that into Hangul. The movie title in Hangul seems to take the Hangul pronunciation of the Hanja.
The character names also resemble the original character names in Chinese; it is an adaptation, after all.
But I am wondering if there is some kind of old Korean Hangul version of 西遊記, that native Koreans pull from. But, the main problem with reading an alphabetic language is that an alphabetic language loses a lot of semantic information, focusing on sounds. It'll be best to read 西遊記 in Hanja, not in Hangul, and understand Chinese grammar. One big difference between Chinese and Korean is that Chinese is SVO, while Korean is SOV.
My other conjecture is that ancient Koreans were well-read in Chinese literature, and Middle Chinese pronunciations of the Hanja became fixed in the Korean language.
Modern Koreans probably cannot read the original 西遊記, because the original 西遊記 was written in 漢字, and most modern Koreans may be educated 漢字 but lose knowledge of it due to prolong disuse. In addition, the grammar in the original source would be another obstacle for most Koreans, while most modern Chinese people can read it with relative ease, like Shakespeare's works to English speakers.
My question is also connected with how native Koreans actually familiarize themselves with the story. Do they read the story in some kind of modern Korean translation written in Hangul, the original story in Hangul, or the original story in Hanja? If they were reading the story in the original Hanja, then do they pronounce everything in traditional Sino-Korean reading?