I was hoping for advice in writing Catelyn, now that I'v written myself into a trap - not Catelyn as a grown woman, but as a girl, living in Riverrun, before her betrothal to Brandon was finalised. Who were her friends, who was she close to? Did she have ladies? Hoster Tully was said to have enjoyed riding around his estates, did Cat join him?
Well, my friend, I have thought a lot about Catelyn and what I have to offer is pretty much my own head canon, but I think it’s informed by canon (book canon, of course. I’ve never watched the show.)
As a very young girl, Catelyn’s mother would have been alive, and I think that Minisa Whent Tully would have overseen Catelyn’s and Lysa’s daily lives, making certain her girls were being raised as proper young ladies. They both would have been so very young at this point (especially Lysa!) however, that I think even the time spent with their mother would have involved a great deal of play as much as instruction. We know from Catelyn’s canon recollection that she loved to play outdoors at Riverrun. As a child she swam, played in Riverrun’s godswood, and even played in the mud. She had a mischievous streak--feeding Littlefinger mud pies, for example. And while I believe she was always a generally obedient child, she was daring enough to do things like play kissing games she knew perfectly well her parents wouldn’t approve of, so I see Little Cat as a bit of a mixture of her daughters in that she shared Arya’s love of adventure and fun, but also Sansa’s enjoyment of more traditional ladylike activities with her mother.
Of course, her mother died very early in her life, and I see that event as affecting the course of Catelyn’s childhood more than anything else.
As to the question of her friends, I believe her closest friend and confidante was her sister (which makes the events of canon even SADDER!!) They made up their own secret code, for heaven’s sake! I am quite certain that as a young child her mother probably also encouraged her to play and interact with other girls in Riverrun--the daughters of the more well-born castle retainers, for example--girls the equivalent of Jeyne Poole or Beth Cassel in Winterfell, for example. But Minisa died before Catelyn was the age most people send their children out to foster anywhere. (Ned’s fostering in the Eyrie at eight was considered early.) I think her mother’s death likely kept her from having significant numbers of noble girls sent to Riverrun to be her ladies. Hoster Tully essentially made her the Lady of Riverrun upon her mother’s death, and his priority was having her run his castle rather than finding her companions. I don’t think that was intentionally neglectful on his part--there’s no doubt he loved Catelyn very much. He tended to favor her over his other children, to everyone’s detriment. But he was a man. He hadn’t really given much thought to the formal elements of the raising of his daughters because that was Minisa’s realm. Once she was gone, he was more than content to leave the girls’ “womanly” education entirely to their septa. (I realize you aren’t writing about Catelyn as an adult, ketch, but I actually see this as a big reason that Catelyn didn’t intervene with or question Septa Mordane’s methods of educating her own daughters in Winterfell as much as she probably should have. Motherless Catelyn Tully had grown up believing the septa had all the authority in that realm.) So Hoster wasn’t exactly sending out invites all over the Riverlands to take in his bannermen’s daughters; Minisa wasn’t there to encourage him to do so; and Catelyn was just trying to be whatever her father needed her to be, take care of her siblings, and mind her septa. So I think that in those moments after her mother’s death when she was still able to exercise her adventurous side and just be a child, she had primarily her siblings and Littlefinger for company. As she was the oldest of that group and also expected to be responsible for them, that set up a situation which sometimes left Lysa and Edmure resenting her for “mothering” them rather than just being their playmate, and left Catelyn a bit isolated in terms of having friends and companions her own age.
As for riding with Hoster Tully around his estates, I absolutely believe she did this regularly. Remember that Catelyn is about 9 years older than Edmure. Because of this, she was the heir to Riverrun for nearly the first decade of her life so Hoster had a lot invested in her. Her detailed recollections of Masha Heddle at the Inn at the Crossroads indicate she’d ridden all the way there with her father on more than one occasion. And of course, there were very few years between her brother’s birth and her mother’s death, so Catelyn had only a very brief period in her young life during which she was not the heir or the de facto lady of the castle. She would have spent a great deal of time in Hoster’s company, learning about the management of Riverrun and the politics of the Riverlands, visiting bannermen with her father, and hosting bannermen at Riverrun. A lot of that would have been overwhelming for a young girl--even one as intelligent and duty-oriented as Catelyn, (which is why I think she continued to escape occasionally to the river or godswood just to breathe a bit and feel the water on her skin or the mud between her toes, a la Arya, throughout her time in Riverrun), but some things--like the horseback rides with her father--are experiences I think she enjoyed greatly. I actually always write her as a very good rider in my own fic, and her history at Riverrun is a major reason why.