How do I add my new wife to my visitation on a closed family case?

The easiest route would be by agreement -- and if you do make such an agreement, you should memorialize it in writing to make sure no one changes their mind later as to what was agreed.  Absent that, you can always file a motion to alter the terms and conditions relating to custody and visitation.  For background, see http://willicklawgroup.com/child-custody-and-visitation/.