Obviously, guitars were smaller than most modern guitars. Nothing worse than a big ol' dreadnaught or a jumbo at a reenactment. Smaller guitars can be found. I have a friend who found an 1890's Washburn for about $600. It's an interesting axe, and looks decent for the period. Guitars like these are relatively affordable because modern pickers have no use for them. Not enough volume, I guess.
Just as important as defarbing the guitar would be defarbing your chops and defarbing your repertiore. Consult period instruction manuals for technique and repertiore. Truly researched guitar playing is something you almost never see in the hobby. There's a lot of cool music out there, waiting to be brought back to life.
"Frank Converse the banjoist, his beautiful wife, and a young gentleman from Richmond, said to be smitten by the latter's charms, skipped away from Petersburg, Va., by the Southern train, leaving the "Converse Opera Troupe" to fufill the engagement as best they could."
National Police Gazette, April 1860