When the enemy has completely built up his castle with walls, it is necessary to block the exit from the gate with a leash for bulls. If you place it correctly, all enemy buildings outside the castle will disappear, and you can safely collect resources with the army. True, after a while, when the computer runs out of money, it will sell the towers and the passage will become open.
You can still wait until many slaves appear in the enemy’s castle, and put a small building in the enemy’s castle itself. When slaves attack a building, a fire starts, and it spreads to the enemy’s buildings.
Stronghold: Crusader: Tips (Blocking the enemy + self-immolating bases)
The same applies to the balits (we put the sawmill and the ballista side by side, and watch how it sets itself on fire)
Good luck 🙂