Guy,
You can download and archive using SDC. Alternatively, you can fit the entire game onto a cd without zipping it, I think (you'll possibly have to get rid of your game saves). The
With SDC there's 2 ways to go about archiving:
1) Highlight the game and right click on it, select download and archive
2) Highlight the game and select file-Archive-selected app
Both these options place a zip file in the backup directory that SDC installed to. The first way will d/l the entire game again, but the second will just backup what you have on your harddrive. Actually, there's 2 options under the second method, one to just back up the app ONLY, and the other that will back up any extra files as well (like mods).
You can then burn these to a cd, and when you want to re-install place them back in the backup folder they were in, and under the menu file-archive-restore existing. Hopefully that'll work, it has many times with me (I like to move things about and re-install frequently), but there's been another thread recently by someone that this wasn't working for. SDC still has a few teething problems, unfortunately. However, it seems to be working fine for me recently.
HTH