I would second the virtual school route. I get what floradm is saying about it still being too easy. That is definitely true, but you have more time on your hands to supplement as you see fit. You can provide your kids with more challenging work after they have completed their daily lessons through the virtual school.

With a virtual school I don't have to worry that I missed something and my kids are not going to get into college because I made a clerical error. I love that safety net.