Thank you for the feedback! Some great points for clarification. :)
What's a good length of play needs to be worked out in testing, I suppose. My estimation was that with a chapter length of about two hours, some setup before that probably takes half an hour or more, we're talking more than six hours for three players. I tend to play short sessions, so that would definitely be more than one for me. But maybe shorter chapters will work better to make it a one-session experience.