Bill,
You might want to take some of the customer's vacation time to look around the admin section and see what can be done from there without having to work with the php files. Currency and Language, for instance, are controlled in the Tools menu under Layout Boxes Controller.
A lot of Zen-Cart "editing" is actually "flipping a switch" in the admin.
If you do get to a point where you're forced to edit a file, be sure to save it to the theme007 override directory.