When a Child has Gone Through the McGuffey Primer and First Two Readers, It's Time to Write
When a child can sound out words accurately, it is time to move on to stories. You can Use the McGuffey readers. If your child likes them, terrific.
But maybe the stories are not interesting. So, try something else. Maybe a book by Thornton W. Burgess would be right. Kids like his animal stories.
Give it a try. If you find that your child likes the first book, think about working on a module for other mothers to use. Use just one book. See how it goes.
Maybe you like another set. There are lots of public domain, pre-1923, non-copyrighted materials out there. He is a site devoted to collecting them.
Don't bite off more than you can comfortably chew. Start with one book or even one story. But if it is a series, it will be easier.
As for arithmetic, use Khan Academy for now. Or use a downloaded volume of Ray's Arithmetic, which is in the Download Library department.
How about working on your own Bible stories? Do a video version of a book like Catherine Vos' Child's Story Bible. Don't repeat her words. Use your own. But tell the story. You can do a talking head video.