@SJohnRoss that sounds like a whale of a time! I suppose a family are likely to have quite a strong shared set of "invisible rulebooks" (to quote... er... you) which would mean they're likely to be on the same page in a lot of ways. A very different vibe from say a convention oneshot.

I've got a video/blogpost in the works about "What TTRPGs Expect From Us" which is going to touch on player expectations and onboarding. The concept of shared invisible rulebooks are likely to feature prominently!