That was quick

This is adorable. Are there any other manga where some of the girls visit the outside world like this?

Can't.. stop... crying.

I would assume that Reimu becoming immortal would be an option too. Maybe becoming a Hermit or a God, where she would have to give up her status as the shrine maiden. Though it's mostly a question of if Reimu would actually do that, rather than whether she can or not.