They've saved up and gone on a cruise about the world and so they won't be home for at least 3 months. (*) saved up (*) on (*) about (*) won't be
This is a companion discussion topic for the original entry at https://english.best/questions/24391,theyve-usaved-upu-and-gone-uonu-a-cruise-uaboutu-the-world-and-so-they-uwont-beu-home-for-at-least-3-months/