When you pick up the Crusade to move; the allowable areas you can move to will be shown.

For the player it tends to be the most direct route possible; Switzerland might be a little too far north...unless you direct the crusade to perhaps Livonia?

Unlike M2TW I don't think you can disassemble a Crusade enroute; it either withers or dies. If you get to Switzerland how will you take the castle?