Titles for "beefing up" Beyond?

[rgrindle]

I'll be doing Beyond with a 6-year-old and an 8.5 year-old combined. I know there is not an official "extension" set, but I love having the extra book list in the back of LHFHG to augment the material for older DS. Beyond has no such list, but I've noticed at least one person here say that they supplemented Beyond. I can't find any actual titles, though. Does anyone have a list or recommendations they could share?

[Tidbits of Learning]

I did Beyond last year combining a 2nd, 4th, and 5th grader. Since the history books were actually CLP 3rd and 4th grade books, I did not stress the history part much. To up the science, we used Apologia Zoology 1 for all of them as well as having my 2nd grader do the science in Beyond. They all did their own grade levels of math, language arts, and reading.

[MomtoJGJE]

We haven't needed to use extensions yet, but my thought would be that you could go through the unit titles and make search for books that go with it? Like off the top of my head, any books on the Mayflower, Pilgrims, Thanksgiving, early America, pioneers, Revolutionary War, George Washington, Betsy Ross, Ben Franklin...