American Civil War Riverine Actions is a set of free wargames rules for ironclads, tin-clads, cotton-clads and all the fun and unique ships that plied the rivers of the United States during the ACW.
The Battle of Blackburn's Ford is an introduction to the Combat Command American Civil War Rules. The pdf also includes counters if you don't have figures.
At the Game Architect blog, you'll find a good looking paper model of a 15mm American Civil War wood and stone barns. The models are in black and white, so you'll have to apply your own coloring.