The Lances of Lynwood, by Charlotte Mary Yonge, who wrote excellent historical fiction for children in the Victorian era. This means the language is interesting, complex, and advanced. This book is set in the Middle Ages.
You may also enjoy these free Kindle titles by Yonge:
The Heir of Redclyffe
Other childhood classics not to be missed:
Alice’s Adventures in Wonderland
Jane Austen, of course, should be in the repertoire of every homeschooled mom and lass, and quite a few homeschooled lads:
For Mom, some Grace Livingston Hill, my personal junk food reading:
Cloudy Jewel, one of my favorites, and a little out of the ordinary.