some questions that need answering(spoilers)

So some of you might be curious like me but I'm curious to see peoples theories etc.

1.so what really confused me was in season 1 and the start of season 2 on multiple occasions we see them come into the issue of that some of them will be sent to the "bad place". i wonder what would have actually happened if Eleanor didn't figure it out.

2.if there is multiple neighbourhoods could Janet theoretically take you to the other neighbourhoods via the train? because that's how they got to the medium place.

3.And when Janet is taken to the medium place how does she function and still have information from the database/mainframe thing, unless the the mainframe is giant but I'm pretty sure they're limited and assigned to that neighbourhood, not sure if that last one makes sense.