Creating Sermon Archive

I have been asked to set up an archive of older sermons as well as the main sermon page on our website. At the moment there are a lot of sermons in the main sermon directory that are orphaned (i.e. the series and sermon details have been trashed from the Joomla backend) - what is the recommended way of setting up a second sermon page and moving the archived sermons there? I can't see how best to do this.

Also, the search for orphaned files doesn't seem to work as that was my first thought on rebuilding the sermon and series info for the old files.

If the items are only trashed and not deleted, then you can restore them easily. Just set the filter to show trashed items and publish them again.
You can then assign a different category to them and show that category in a different menuitem.

Thanks for this - following on, is there a way to bulk change the category on the trashed sermons rather than doing it one at a time? e.g. if I change the category of the series to 'Archived' or something and then republish the sermons will they inherit the category of the series automatically?

You can bulk change items using the "Batch" button.