Challenge mode: make it so that Miku will always travel directly from start to destination without passing through any other station in between.
(Not guaranteed to avoid deadlocks)
(Seed: 9218)
N.b.As far as I can tell, even if two routes from start to destination are exactly the same length, Miku's pathfinding will take her via the route with an extra station, so you must always make sure the station-free route is strictly shorter than the route with an extra station.
Would love to see what other challenges people have tried!