Kubuntu: Linux For my Mother?

I've just finished reading about apt-proxy which is pretty much what you are looking for. It caches everything you download, including security updates and patches. All you need to do is change the sources.list on your other computers and they will download from the cache. It's looks very easy to do and doesn't take much storage space because it's only caching what you need

 

exactly what i was looking for, thanks mega!