@a_5mith said:
@Tanner Yupp.
Go into category permissions and tick Find Category for guests, but leave everything else unticked, then tick everything for registered and admins and any custom groups you created, they'll see the category on the home screen, but need to log in before they can read, see here: http://35hz.co.uk
Click A-Z of production.
I was hoping for more of a one-click "Make Forum Private" solution but that answers my question, thanks