I think there should be an option allowing you to view your neighbor's activity. In example, there would be something under their name that shows how many days they have been active. If they were inactive for a week, it would say Last online: 7 days ago

If you were recently just on restaurant story, it would say Last online: A few minutes ago

I hope you can consider this feature to be added to the game, and I feel that this can help other players sort through their inactive neighbors easier.