According to the story's timeline, the Akan and Kunte Kinte discuss running north to the safety of the abolitionist movement in the late 1700's. The abolitionist movement was a fringe movement until the early 1800s.
When the Slave Doctor is examining Kunta Kinte in Annapolis in 1767, he is singing and humming "Pop Goes the Weasel". The music was written around 1799, and the full lyrics were published in America in 1850.
Much of the topography and flora throughout the series is wrong for the areas in which it was set. The Reynolds plantation, in Spotsylvania County, Virginia, is in a mountainous with a lot of plants native to dry areas, like Southern California. In real life, Spotsylvania County is flat and rainy.