Possible Clues:

• One of the swingers gets letters on the way in
• Side of an entrance
• Theatre gets letters of support on the way in
• Theatre gets letters from one of those for support on the way in
• Upright beside a garden entrance
• Get a new job as agricultural supporter?
• Theatre appointment is a mutual confidant of you and me
• River behind theatre on street offers support on the way in
• Entrance support