While Megan and Cara are talking and sharing ice cream on a couch, Cara says that she is really 31 and the ice cream container is in Megan's hand. In the next shot, the container is in Cara's hand with no exchange taking place.
Cara is signs a letter to send to the author and puts it in a priority mail envelope. She then folds the edge over to seal it, but she never removed the protective strip, so it wouldn't have stuck.
From the gas station, it is an hour's drive to a diner, but only minutes to a nice motel room.