Possible Clues:

• Forest or park keeper
• The outdoor life for him is all the rage at last
• Keeper of national park or Texas policeman
• Does open work make him cross when he loses his head?
• One works out the rage at last
• Cross off his head to make him cross for outside work
• Rover shows Rex extreme displeasure
• R wrath?
• Person with binoculars
• Cross off the head of the worker outside to make him cross