Well, I don't know the first part of the answer but you could create a new library just containing your playlist, set it to play but not repeat, so when it reached the end it will simply stop playing. iTunes will still be running though, so I'm not sure if you need it to quit after playing the songs.
Just hold Option as you launch iTunes and it will show the above dialogue. You can't run 2 instances of iTunes libraries AFAIK, so you need to know that, but there are many other media players out there if you did need to run another simultaneously.
If you are running Tiger you can use iCal to schedule the workflow:
- Save the Automator workflow as an application.
- Select Add Alarm on a new or current event.
- Select Open File: Other, and open your saved workflow application.
- Enter the time and date that you want the workflow to run.
- If iCal is not running at the scheduled time, the workflow will run when iCal is next opened.
You can configure iCal to launch at login if you like.
Just right-click iCals icon in your Dock and you'll see the above options.
I just went ahead and was able to create a workflow that would launch iTunes.
Next step is to 'Save As" an Application in:
Workflows ~> Applications ~> Finder
This places it in your right-click contextual menu under Automator. (not sure if the workflow only needed to be installed in Workflows ~> Apps, or not?)
Now, I'm no expert on Automator and I really only had the idea about iTunes so please understand I haven't tested this to see if it truly meets your expectations. There may be another easier way or fine tuning needed and someone else may jump in
(please do) with further ideas or proven methods.
EDITED TO ADD
If you are running Leopard I just found this:
Workflow Looping
Repeat a workflow for a specified number of times or a specified time duration. No more need to save as an iCal plug-in or use the Automator Loop Utility.
