Telling Renée goes better, sort of, than telling Charlie; she cries, but she's less shellshocked, and takes reasonably well to having her adult daughter who happens to be legally and visibly ten (then eleven) around.
Chris migrates herself and James to Phoenix in Isabella's same school district and both ostensible children manage to skip into the sixth grade. This will provide culture and social opportunities with people slightly less... eleven... and also give Isabella an excuse to be unfamiliar to her classmates; someone who knew her before might notice.
They get nearly matching schedules and wade into middle school. It is nightmarishly educational. Being in their mid-twenties gives them some perspective on the entire thing and having each other is an improvement but Aslan's fangs these children.
However, it is through a school person that Isabella discovers a relatively accessible way for them to not get rusty on all their Narnia skills. She promptly joins the Society for Creative Anachronism.
James joins up right along with her. It sounds like a good way to maintain assorted Narnia skills. And practice code-switching. She kind of likes the idea of getting to keep her Narnian accent in some contexts, and the SCA sounds like the sort of context where a Narnian accent is appropriate.
She participates in some of the Youth Combat stuff with the SCA, too, to get used to the way they operate, even though she won't be allowed to do anything with even approximately real swords for another three years, ugh, childhood, why.
"Argh," James agrees, leaning on Isabella and hugging her. "I tried not to hope. But - Father Christmas is so good. Maybe there's some way - there are magic things that work here - if we could figure out how they work, and why... that almost seems like it would be worth having us here for, you know? If we could make Earth into a magical enough place for Father Christmas to visit. I think he implied that's why he can't."
"Yeah, we have a really bad information problem." She yawns. "But it'll give me something to point myself at that feels more important than math or becoming King of Atenveldt. Even if it's difficult and we have next to no leads and it might take years just to find out whether there's even a third magic thing in the world."