If the intranet users are connected to the internet so it can load the google javascript, it should still log to google analytics. Though I'm not sure what their policy is about intranets. In order to activate google analytics you have to upload as file and google has to be able to retrieve it. So, if its an extranet, ie an internet web site but only authorized users can sign in, that should work fine, but in a real local area network it may not be possible.
There is nothing in mojoportal to provide any rich traffic analysis, the logs are the best bet. There are various free and commercial log analyzers that provide good reports.
Best,
Joe