Planner for plotting multi-character, short-timeframe story arcs

Are there parts of the story-development process that confound you more than others? I’m currently struggling with how I best want to depict a week’s journey with close to a dozen characters. I know their destination, but never plotted out what, if anything, happens along the way. I know there is important dialogue and interpersonal dynamics that have to happen, but haven’t yet cracked the code on how best to present it. I’m not really looking for answers. I’ll figure it out, but as I do, it got me wondering what areas of your story building do you often struggle with?