I think the details of the mission itself might need to be what we'd like to do. We can have it be a one-hit wonder where they spend the night at Tanzaku and manage to deal with him the next day, or they're ambushed on the way into Tanzaku, meet Taro and the Sound for the first encounter, then after dispatching some of the fodder they retreat for the time being. Kakashi and Sakura are a little ragged from their travels and have to recuperate after the skirmish. Kakashi can need recovery due to using his Sharingan, or Sakura can be somewhat injured and Kakashi can find them a room for her to recover for the night. It can be very similar to the Zabuza arc itself.