I don't know my Star Wars history that well, but how about some fictional battles out in the outer rim. Perhaps a Rebel/New/Old Republic task force that was cut off from the main fleet, stumbles across some Imperial outposts which is secured and eventually guides them to the construction site of a super capital ship, SSD maybe? An Imperial campaign could be task place during the destruction of the Old Republic, stopping Republic attacks and assaulting planets and bases, same during the times of the Rebels.