If you don’t have a lot of experience in writing CYOA’s, I would suggest you to start small. Don’t go for 70k words right away. For your first project, try doing a story structure which has relatively few branching, like the gauntlet style, rather than something like a time cave. Branching tends to get out of hand relatively quickly in CYOA’s and main reason for people leaving their works unfinished, is because they get overwhelmed.
