Unfortunately there is no "good" answer to your question because the H5 developers did not put enough intelligence into the AI to handle caravans properly. While you might be able to add that intelligence by scripting, it would be a very complex script and I would not suggest that you even try.Hiya. How do you all prevent, "custom made maps" the pc from getting so many caravans that they block his own entry/exit from his castle? A human has to downgrade creatures, allow caravan to put them in the full castle, and then re upgrade them. But when a pc castle is full an upgraded, their caravans are stuck at the castle entry. What to do?
Your best bet is to ensure that there is a LOT of empty space in front of the AI castles so that there is room for the piled up caravans to spread out. I've had to do this design in all of my maps. It is not a perfect solution, but it usually mitigates the problem to the point where the AI can still function.