Well, it can go either way. Sometimes the visit might be a true account of something that happened, but often there's some creative license taken to make it more interesting or to fit a certain theme.
It depends. Sometimes a visit might be based on real events, but it could also be fictional or a combination of both.
It's not always straightforward. A visit could be inspired by real-life experiences, but with fictional elements added for entertainment or to enhance the narrative. Or it could be entirely made up.