I really like Zombie Cave: simple, with clearly defined goals. Failing the addition of new maps for the scenario, are there any other similar mods out there?

I don't think anyone's made extra control chip maps, but there are plenty of missions to download that have clearly defined objectives. The Prison Escape series and SHIELD: Under Siege are great to start with, and they shouldn't be too hard to get working if you encounter problems. If you get an error, start by reading the first post, then go to the last page and work your way backwards. I can almost guarantee someone will have had the same error and was replied to with a solution. You can PM me if you need any additional help getting a mission to work.