How are you? Well, I hope. Happy Friday.
1) How much space do these project files take up (without the media files)
It depends on the contents of each project. I can be only kilobytes, or it can be 50MB. Let's just say that these files are usually not large. However, you add together 100 of them and they will add up. The few productions I have are much smaller, like 20 projects. These take up a couple hundred MB.
2) Is there a process for archiving these old projects while maintaining the cohesiveness and functionality of the production?
I think the PDF covers this when migrating versions, etc. Have you read it? Here is a link. Let me know if you have further questions.