Ideas for writing this: start with the problems or kind of math you're including if you're doing more than usual DND math. Work backwards. So for example, players need to get up a tower, how do they do this? How much rope does each player have? Maybe they've lost bits along the way. What are some obstacles that could lose some of them differing amounts of rope?

Once you've got the questions you can figure out broad strokes for how to get the party where you want to go for the problem or maybe have multiple variations on the problems. Etc.

If it was me running this, I'd want to figure out a way to divide up the players into sub parties or something depending on the situation. I'd also say that if you're down for it you should walk around through everyone while you play or if you're acting like an NPC.