Let's get the overall plot wrap-up out of the way quick:
- Capricorn dies.
- Meggie's mom is back in our world, reunited with Meggie and Mo.
- Dustfinger goes off a-rovin' (with Farid tagging along).
- Elinor hates people less.
- Basta gets away.
As for the very end of the book, we see Meggie getting to know her mom again (yay) while living with her family at Elinor's place. Meggie also decides to become a writer, figuring "where better could she learn that trade than in a house full of magical creatures, where fairies built their nests in the garden and books whispered on shelves by night?" (59.28). She's got a good point about her surroundings, but her reason for wanting to write goes beyond living in a house inhabited by creatures read out of other books' pages:
She wanted to learn to fish for words so that she could read aloud to her mother without worrying about who might come out of the stories and look at her with homesick eyes. (59.27)
In other words, it's also a matter of safety—for both herself and book characters. After seeing how much pain and awfulness can come from getting read into or out of a book, Meggie wants to write some safe places to read aloud about.
So over the course of the story, we've gone from Meggie not knowing her mom, like, at all, to making a major life decision about her future profession based on wanting to connect with her mom over reading aloud. This is also more generally a reflection of how Meggie wants to take control of her life: people being read into and out of books forced her and her dad to live in hiding for a long time, and now she wants to take charge and master that skill and related skills (like writing) for herself.