We used mostly CM methods only for grade school through almost all of middle school. We started adding some more textbookish books in middle school for science but we used them in a very relaxed manner and combined them with reading from living books.
We also use textbooks for science in high school and have begun using a textbook for our history spine as well. We’ve also begun using a writing program 2 days a week.
Charlotte Mason did use textbooks sometimes with her older students and she also taught more formal writing methods at this age.
When my kids were little, we mostly used library books for science and history and literature. We also followed Charlotte Mason’s recommendations for language arts in our home. I did start using IEW with my son when he hit middle school but I chose not to do that with my daughter and I trusted CM methods. I have been very pleased with the results!
I confess to allowing my children’s interest to guide their science studies. Finances were tight so I needed to make as much use of our public library as possible. I would have my kids pick a topic and we would go to the library and they would get various books on that topic and read a bit, each day for science.
We always did history chronologically but used mostly library books for that as well.
I used free book lists online and from catalogs to choose our literature and history readings. When I couldn’t find a certain book, I would look for another book on that topic. I found many treasures this way.
We never read Jack’s Insects. My children and I really enjoyed Thornton Burgess’s nature books in the elementary years.
How old are your children? We might be able to give better advice if we have more information. 🙂