I would not stress out about science and history in these young years. I would be very relaxed and enjoy it with your kids. I would also recommend NOT testing them in any subject- it may sound strange but many people refrain from testing especially in the early grades.
We love Story of the World for history but Science has really been a challenge. We have tried Apologia but just don't stick with it. Lately we have been using a bunch of anatomy stuff I got at Sam's and Costco back at Christmas. There are so many supplies and resources online to make your own curriculum but it takes a lot of work (sometimes).
