However, the single sign on seems to have negated those $wgGroupPermissions settings in LocalSettings.php. As in, I can log in with my network password, then log out, but still see and edit pages. Any ideas?
The method posted on that site uses an auto-authentication plugin. As long as you are authenticated to Apache, you'll be logged into the wiki - no logging out until you close the browser.
I recommend using the LDAP Authentication plugin. It'll do what you are looking for.
http://www.mediawiki.org/wiki/Extension:LDAP_Authentication
http://www.mediawiki.org/wiki/Extension:LDAP_Authentication/AD_Configuration _Examples
http://ryandlane.com/wprdl/2009/03/23/using-the-ldap-authentication-plugin-f or-mediawiki-the-basics-part-1/
V/r,
Ryan Lane