Does the story make use of symbolic settings?
I would suggest that the "restaurant across the highway" where the older kids all hang out at is used symbolically. It is a place where the "cool" kids gather; they are older and envied by those who want to be considered "cool." This is a place where there are no adults to "rain on the parade," though this seems a little unrealistic. The fact that it's in a part of town that is not frequented by the general public (across the highway) guarantees that there won't be people there that will send their youngsters home.
In that this place is off the beaten track and not "policed," it is a perfect place for young people to act in a way they would not at home. They will make connections there that are not the "usual" kind. It is here, of course, that Connie sneaks with a friend, and it is here, also, where Arnold Friend fatefully notices Connie.
The restaurant is symbolic of the places one goes outside of the sphere of his/her normal experience: it is a place where the general rules don't apply--where rules may even be suspended completely. It is unknown territory which can often present unexpected challenges or unknown dangers. In this case, the restaurant provides a setting where Connie pretends to be older and more sure of herself, and in doing so, "travels to a place" (her ultimate meeting with Arnold Friend) from which there is no return.