Well I have not done sotw in months, so take this with a grain of salt. :)
If I remember correctly I only read about one page (2?) from sotw at a time. After that I'll get something for them to do while I read a book. generally, it was just one book. Any others that I've checked out would be for later. I never had a whole lot checked out. Generally just 1 or 2 more.
With science, I just read it during lunch or when the 2 year old naps or when the 2 year old is busy. Fortunately, all 3 like the let's read and find out series. I may end up reading the fast version though if my 2 year gets restless. :)
For bedtime, we read books that they enjoy or classsic books or read poems or listen to classical music/hymns. Fortunately for me, they like the mathstart books and sir cumference books and I can read them anytime.
We are more science and math type of people than history, so I don't know if that has any influence in my decisions.