Well, open the view a bit on the mission design. I tend to look at the design first with simple terms, then build upon those any additional complexity I need.
Consider the big pieces are the Hazards of Mice, Animals, Weather, and Wilderness. Each of those hazards alone might create many obstacles to manage. Aside, I treat the hazards as interruptions, disruptions, interferences, or distractions from the assigned mission. For example, it is not a wilderness hazard because they are told to trek from point A to point B; it is a trek they are assigned, and the wilderness as a hazard is making it harder to complete.
Any given hazard can generate one or more obstacles. Let’s use the wilderness. It might be terrain changes over a lengthy trek: barren land, soggy marsh, overgrown meadow, ominous wood. In each of the obstacles, the GM has a reasonable idea of the test needed to overcome that obstacle.
- Crossing barren land exposes the patrol to overhead threats; a test of Mouse Nature (hiding, escaping) is needed
- Crossing the soggy marsh is best with a hasty boat; a test of Boatcrafter is needed, but perhaps an alternative of Pathfinder would suffice for a good route
- Cutting a path through the overgrown meadow calls for a test of Laborer, but an alternative test of Health might suffice (stamina and endurance clearing a path)
- Sorting the way through an ominous wood might be resolved with a test of Scout, but an alternative test of Will might suffice (courage and acuity remaining safe and calm)
Then, table chatter might allow the patrol some potential for different resolutions. Maybe they suggest something that works really well for their PCs’ stats or another point of view on the story.
- Barren land would be eroded dangerously if there were a storm; better have a test of Weather Watcher to ensure safe travels
- Soggy marsh could have valuable herbs, if we’re allowed to search; perhaps a test of Harvester permits the patrol to move slowly and gather medicinal herbs along the route
- Overgrown meadow invites snakes to take shelter; we should test Hunter to drive off potential threats to other traveling mice
- Ominous wood is probably home to many sorts of birds; we should test Loremouse to call a friendly beast of feather to guide us safely
The GM can use the table chatter advantageously or stick with the initial plan. In either case, you’ll need to have a few reasonable ideas for the outcome of a test.
- Barren ground will have no food or drink, so a failed test is likely to create Success w/ Hungry/Thirsty
- Soggy marsh will create fatigue, so a failed test is likely Success w/ Tired
- Overgrown meadow provides cover for many unknowns, so a failed test is a good candidate for an animal twist (like a snake, as suggested by the table chatter)
- Ominous wood generates frightening reminders of childhood fables, so a failed test might lead to Success w/ Angry (disturbed by fear)
Each hazard can generate one or more obstacles, and some obstacles will be complex enough to create more than a simple test. So, this gives more tests for the players to gain checks, and probably drives longer GM Turns. So, find a balance that works for your group over time, and change from time to time to keep things a bit unpredictable.