When new writers approach a publisher, they are usually told not to think about publishing a book until they have three written because the work involved in marketing just one book isn’t worth it. Three books, on the other hand, provide time to introduce both the series and the author and to get readers who liked the first book eager to read the second and third.

So my suggestion is to turn the story into a trilogy. It’ll be easier for readers to digest a little at a time and will be way more marketable than a single, long book.