I've been thinking of "Summer Song," in which Norma invited the family to play the alphabet game en route to Ocean City. Specifically I am thinking of what sounded like "There's A in Danville." As much as I want to avoid criticizing Norma, that sounds like a "cheap" way to play if she were to point out words containing the letter instead of words beginning with the letter.

Then I remembered that there exists a city called Annville in Pennsylvania on US 422 between Harrisburg and Reading. Say the names Annville and Danville, and they sound very similar. Might Norma have noticed Annville instead of Danville, as if the Arnolds were traveling through Pennsylvania? New Jersey, to the east of Pennsylvania, has a very prominent Ocean City. So does Maryland, to the south!