Remathilis
Legend
Rather than giving your players a menu of tasks to choose from, I would set out the scenario and give them the intel I wanted them to have on the approaching enemy, then simply ask each of them what they want to do and how long they plan to spend doing it. Maybe suggest half-day or full-day efforts. Let them come up with the ideas.
The leader of the Rebellion will suggest a few things (aka the list) if they don't know where to start. They are free to come up with others if they want. The idea was that they'd get one important thing done a day; along with minor things, etc.
This isn't supposed to be a big part of the adventure; the battle upcoming will be much bigger. Its more to give them a feel of preparing and have that feel reflect in the later combat without getting into the nitty-gritty of actual tactics and stuff. Even moreso, what I posted was my DM notes; a lot of these events will be given some "meat" via role-playing and description much like how a combat can be given vivid description rather than be reduced to a series of dice rolls and number calls.