I like SOTW and its divisions, so if I were to run two concurrent streams of history, I'd start modern with the beginning of volume three, thus each stream would eventually cover two volumes of SOTW. You'd also be able to keep your history moving at comparable paces, if that's a goal of yours.
I've only browsed Muse in bookstores and haven't seen Ask, but I grew up with Cricket, and my family has loved Click, Ladybug, and Spider. The content is great, age-appropriate, and curiosity-inspiring. I can't recommend this publisher enough.
HTH!