Quote Originally Posted by Delenda est Carthago
If, for example, i wanted to script it so that an AI army went from point A on the map to point B, moving every turn, but not in the player's control (i.e a computer controlled opponent) how would i do it? Is it possible?
Yes, you can, but you need to make sure that no other AI faction attack your army on the way to it's destination. So it works best if the army crosses its own lands or passes through friendly ones (military access granted).

Here's how you can do it (based on an ideea originally by Myrddraal):
1) You decide for a position were to "hide" that captain. The best would be to create some sort of "labyrinth" of impassable forest and hide your captain there. Unlike generals, captains are immortal so they can wait in hidding for hundreds of turns.
2) When time comes (an event trigger or a certain turn) you give your captain his army (command_console create_unit ...) then you move him out of the labyrinth and towards his target. You should know how many turns it takes to get him to the intended destination so at every turn your script should check what turn it is and if it's still "early" to order him to move forward.
3) You may want to send your captain to his destination at a precise moment in history because otherwise (random event-triggered departure) you need to go through hoops in order to preserve the information about how many turns are left till he reaches his destination.
4) Your captain's army might get attacked on its way to the destination. If the captain is killed, no more expedition. If his army is only defeated, you could replenish it like they do in Prologue but it will be probably impossible to find out where it ran away and how to get from there to the original destination.