I have 2 loops of track that I run on my hardwood floors and have been doing so for the past 2-1/2 years. The outside loop is approximately 8' X 32' and the inside loop is 6' X 30'. The straight going down the hall connecting the living room and dining room is about 27'.
Since I'm running Chessie trains exclusively I made sure to paint my interior walls yellow, orange and Enchantment Blue so the train would "blend" in and become part of the decor. Just kidding...