Scripts for beginners.

Hello again. I need some scripting help once more.

Here's the situation: I've divided the map into two parts, connected by a garrison. After the garrison, I've placed a region and prevented the AI from entering it. I'd like the region to be removed after a certain amount of time, allowing the AI to proceed.

Also, if anyone knows, could you tell me how to implement the appearance of caravans with troops every month, and have them travel directly to a city? Yes, just like in the final mission of the Arantir campaign.

Thank you in advance.