[ one out of three isn't bad for a first impression! river smiles and tilts her head as she thinks about this, clearly more comfortable talking about space than magic. ]

Seen is harder to answer. Serenity has a few windows and you can see lots of stuff in passing. The 'verse is big and not all of it is habitable.

[ not for a lack of trying. river looks down and kicks her feet a little as she keeps talking. ]

Visited is a little hard to answer too, because she's not always allowed to leave the ship when we stop somewhere. In total, I think it's... six planets and four moons. Approximately.