Creating a keyboard shortcut for "Show Path Bar" in Finder
Go to the Keyboard preference pane in System Preferences and choose the Keyboard Shortcuts tab. In the left column, choose Application Shortcuts like shown in the image below.



Click the plus button and add a keyboard shortcut entry for Finder for the "Show Path Bar" menu item. Since the title of the "Show Path Bar" menu item changes to "Hide Path Bar" once the path bar is shown, you might want to add a shortcut for that as well.