Ok, you are beginning to not make any sense to me. Is this script timed or not? You've posted :
It would be a script that I would set up to run, say, a couple times a day.
and later said
However, this isn't a script that gets run on a timed basis
Also, I don't quite understand why you want a loading screen. I don't know how you expect all the processes on the site stop and I don't understand why you would want that. Could you let us know exactly what you are trying to do?
Some code examples would help...