I havent the foggiest notion how to homeschool, living in a country with universal preschool and mandatory brick and mortar schooling, but if my four year old wanted to do "school", this is what I would do:
Take her to the library, non-fiction section, discuss what you want to learn about and take a stack home. Make a big deal about choosing to read one to her "todaaay - a lesson about volcanoes." Choose books with lots of pictures and flaps so she can amuse herself leafing through it afterwards while you diaper or feed the youngest.
Then, fiction section, for reading. Choose a few books she wants to read with you, then read slowly while following the words with your finger. Thats reading lessons covered. Have her look for easy sight words. And if you need a bit of time for other stuff, let her go to town with starfall.
For writing: lots of fridge magnet letters, give her letters to find, words to compose, while you make dinner.
For science: take her to the grocery store, teach her about fruit, veggies, meat and fish. then protein, carbs, fat. make sure some of the non-fiction books you choose from the library are about farming, food production and the human body. Follow her lead. And have some kiddie science videos ready for when you nead an uninterrupted half hour. Dinosaur lesson!
For geography: sit down with google maps and earth.
For maths and fine motor:
Print our dot-to-dot and mazes.
Thats quite a few lessons covered, no? I bet you are doing most of this anyway, as this is really just how to parent any bright and curious child, you may just have to be a lot faster with having stuff ready for her. It can all be an organic part of your day, and will pleasantly feel like school to her if you structure it like school.
