Back then, often movies would show first in big cities, and then move into suburb theaters if they were popular enough. It's a sly and effective joke.
This kind of personal devaluation from both Violet and Patty will only get more common in the future.
Charlie Brown is becoming more of a straightman, someone who reacts in funny ways to the foibles and antics of the other characters. Given Schroeder's past reactions to more modern forms of music, his willingness to (I think we're supposed to assume) adapt Beethoven into a mambo seems kind of sacrilegious of him.
Actually, I think Lucy has given Charlie Brown far more than half of that piece of bread. She still calls it "bread an' butter," I notice.
You can tell what people are eating by how many decibels their chewing noises rate, although in Charlie Brown's case we might have to move up to the Richter scale.
Lucy's power to impress with a quiet word is matched only by her ability to do so by shouting, although this hasn't really been established much yet. Notice that Schulz has drawn her words a little differently than usual; they're wider and the strokes are thicker, almost like block letters. She is obvious using some of her infernal power here.