Other than her grumpy but loyal buckskin, she'll also have a rooster as a companion. The rooster will have his own perch on the front of the wagon and will announce her arrival in towns with his crowing. At least once, he'll save her life somehow.
She'll visit some towns on a semi regular basis. I'm considering making it a 'look for the town for me' kind of story, so that there'd be a life goal for her. It could be an idea she could grow into gradually.
Self reflection can occur through her letters to the head of the orphanage. One of these will accompany each story as a form of narration.
For reoccuring characters, there'll be a traveling carpenter she'll periodically run into. He'll be a dashing hunk, naturally, and the only one who really understands her. Maybe there'll be a matronly woman in a 'city' who runs a fabric shop, too.
I've also considered simple sewing projects for the readers in connection with the story.