If I understand correctly, the way these novels were passed around was by some sort of mail-order rental system. According to Elizabeth Jenkins' bio of JA, one of the names on the subscibers' (borrowers) list of one of the first prints of Camilla was "Miss J. Austen, Steventon."

The same bio says that one of JA's favorite novels was Sir Charles Grandison by Richardson, a book mentioned in Chapter 6 of NA as one of Mrs. Morland's favorites and one which Isabella calls "an amazing horrid book." The bio says that it was more moralistic than other Richardson novels, which is probably why Rev. Austen permitted it, and that Isabella disliked it was a commentary on her character.