I would definitely hold off on Apologia if you want to use it with both. We use their materials and have used it with multiple ages and grades successfully for several years. Our oldest is no longer studying them with us, but the younger 5 are: ages 12, 9, 7, 6 and 2 tagging along.
We have used Apologia Flying Creatuers, Swimming Creatures and Land Animals in that order (1 per year for us), and then we used Botany this year. It didn’t take the whole year. We will be using Atronomy this coming year with a 6th grader, 5th grader, and two 1st graders. I am still thinking on assigning extra reading to go along with that, but some are already applicable like 5th grader’s Along Came Galileo, which is suggested in the SCM guide. So I don’t know. Maybe something for 6th grader. I also found some wonderful old books at our homeschool expo, and have those out already on our Nature Shelf (and inquiring minds have been interested).
I would say you could keep it very simple for science, doing a lot of nature study and just going to the library and checking out living books on certain subjects of interest (whether it be animals, plants, space, geography, etc.). You can find tons of stuff on the internet to correlate with that, and of course add in some field trips to the zoo and/or science centers when you can. That is truly enough for 1st/K.
We did read the Christian Liberty Press Nature Readers 1st and K this year, and I just love these books (and so do our children). They are very inexpensive whether you buy new or find them used. That might be a good choice if you want to feel like you have a set thing to read along (and then you can add in other books of interest).
For history, I wouldn’t start an SCM module until 1st grade and honestly my two 1st graders are already 7 and almost 7, so holding off for a 6 and 5YO is not bad in my opinion. Again, you could take field trips to area historical sites or ones you encounter on trips, and read living books about historical figures. Audiobooks might be great too.
We love Your Story Hour around here and you can access a limited number of them on-line for free here: http://www.oneplace.com/ministries/your-story-hour/
You might want to pre-listen as sometimes it is deep subject matter, but I feel it is handled well. They do add in music and stuff, so you just might want to make sure you feel it is appropriate for your younger children. New ones are added each Sunday night (and some older ones are removed).
Oh and yes, James Harriot’s Treasurey, I second that. We read that this year and the children loved it. BEAUTIFUL artwork too.
