We (the younger kids and I) are in the middle of our second year of studying American History. I use Sonlight 3 and 4 as a skeleton and add on lots of different materials. We did this with great success last year. (You can see the complete year here.) We finished Lewis and Clark back in September and then began reading about the westward expansion; however, I decided to plunge ahead with slavery and then the Civil War now, and then we'll spend several weeks later discussion the Oregon Trail, etc.
So here's what we've used for our unit on slavery.
From Sea to Shining Sea: Chapters 10, 11, 16 (This is our primary text.)
Freedom Train: The Story of Harriet Tubman by Dorothy Sterling (This is an excellent book; please don't leave this one out!)
Harriet Tubman (Animated Hero Classics by Nest Productions): I was not crazy about this video. I'm going to try to find and preview the movies Race to Freedom, The Autobiography of Miss Jane Pittman, and/or A Woman Called Moses as the biographical, animated video fell way short of telling much of Harriet's story.
Frederick Douglass Fights for Freedom by Margaret Davidson (I loved this as a child and was thrilled to find it at our local library sale for a quarter!)
Uncle Tom's Cabin (Young Folks Edition): This is essential, in my opinion, because so many other books refer to Harriet Beecher Stowe's book as pivotal in the recognition of the evils of slavery in America. Although I had a copy of the book, this children's edition is available online, too.
If You Traveled on the Underground Railroad by Ellen Levine (I think this whole "If You..." series is fantastic)
Under the Quilt of Night by Deborah Hopkinson, ill. by James Ransome (nice picture book about one family's journey on the Underground Railroad)
Show Way by Jacqeline Woodson, ill. by Hudson Talbott (Traces the author's heritage from mother to daughter back eight generations, with a wonderful thread of quilting, piecing together, writing, and freedom. Love this one.)
Alec's Primer by Mildred Pitts Walker (Picture book retelling the true story of Alec Turner, born a slave in 1845, who was taught to read by his master's daughter. Ultimately Alec runs away from the plantation to join the army during the Civil War. We loved this story because it is based on a real person.)
The Wagon by Tony Johnston, ill. by James Ransome (Wonderfully poetic story of a child born into slavery and his subsequent freedom after the Civil War.)
"The Tale of 'Swing Low, Sweet Chariot'" from The Children's Book of America by William J. Bennett
Addy: An American Girl series
My America: Corey's Underground Railroad Diary (3 books in series)
I Have Heard of a Land by Joyce Carol Thomas (about the land rush in the late 1800s, post-Civil War)
In the Hands of a Child has a slavery lapbook. I downloaded this once when it was free from CurrClick, but I thought the information was too ponderous for my 2nd grader. I'd recommend it, though, for grades 6 and up. The Homeschool Learning Network also has a Harriet Tubman unit study for only $3.50. While I felt like reading the literature above was an excellent study of slavery in America leading up to a study of the Civil War, I think the lapbook and unit study would be an excellent addition for older kids.
Next up: the Civil War!