[Reaper63]

I'm of the mind that the Battlestar would have been under construction or space trials in a restricted part of colonial space. Probably furthest from the Cylon Alliance border as possible. (other side of the colonies) There might be a civilian population center close to it (there are refernces to outposts not on one of the 12 colonies in the series - Ice Station Thula for example)

I'd say when the Colonies are attacked, and the Fleet destroyed (except for the Galactica) This ship would finish construction as fast as possible, and then start ity's new mission, either trying to retake the colonies or finding a new home, like the Galactica.