The battle scenes were filmed using hundreds of Civil War reenactors who were paid as extras but who supplied their own uniforms, muskets, etc. The first large battle scene shot (Manassas/Bull Run) was such a spectacle that word went back to Hollywood and the later battle filmings were visited by some of the principle actresses, including Kirstie Alley and Terri Garber, who posed for photos with the reenactors.
Tom Carter, the drummer boy who joined the 1st US Sharpshooters under Col. Hiram Berdan, was based upon the real-life John Clem, a drummer boy who joined the 22nd Michigan Infantry at the age of 10, and became the youngest Non-Commissioned Officer (NCO) in US military history, when he was promoted to Sergeant at the age of 12 in 1863, for bravery at the Battle of Chickamauga. Clem retired from the US Army in 1915 as a Brigadier General, the last Civil War veteran to retire from the Army, and was promoted to Major General by a special act of Congress in 1916. Clem passed away in 1937 at the age of 85, and is buried at Arlington National Cemetery.
Kirstie Alley, who played Virgilia Hazard, got a chance to act with her then new husband Parker Stevenson, who took over the role of her brother Billy Hazard in Book Two: Love & War. [In Book One, actor John Stockwell was 'Billy'].