Possible Clues:

• 'You're a Good Man, Charlie Brown' song
• Words on Lucy's "Psychiatric Help - 5â" sign ... and a hint to 20-, 33- and 39-Across
• Words on Lucy's 'Psychiatric Help - 5¢' sign ... and a hint to 20-, 33- and 39-Across
• Sign on Lucy's 'Peanuts' booth ... or a hint to this puzzle's theme
• Alternative title for this puzzle
• Title of this puzzle, and what 19-, 29- and 44-Across and 15- and 33-Down have in common