Static HTML IIS website GUI updated

This is a static HTML internal company website that needs the GUI updated to be more user friendly. No back-end changes wanted, just re-arranging panels/buttons to make more usable. Some parts of site will be removed. I have attached a redacted screenshot of the old site and a mockup of what the new one might look like. I am open to Wordpress or just leaving it running in IIS. I want to keep the scale of the project focused on UI updates and not over-complicate. This could lead to longer-term relationship for maintenance etc as the primary programmer is now a consultant.