Have you take a look at Options Page Add-on for Advanced Custom Field?
http://www.advancedcustomfields.com/add-ons/options-page/
I created an option page for my client once where they enter promotion content once in that options page, and display that same information elsewhere via widget, shortcode, and PHP functions.
It costs 25AUD but it’s unlimited license and is well worth the price. I bought all of their Add-ons and it saved me a lot of time making client friendly stuff like that.