Friends question: what would you do?

I have a casual friend – a member of a local band I follow – who has said to me several times, “You should stop by some time.” It is not a dating situation, he lives with his fiancee and she would probably be there. This is about the casualness of the invitation. I would like to visit; but would not just stop by. Am thinking of messaging (on FB) and saying, “I’d like to come visit. What time would be good this week?” Or is that too bold? The last time he mentioned that theirs is a casual beach house and there is always food around so I think he meant it. But…what do you think? I could just say something next time I see him.