Mission 4 (Reclaim The Skies) in Campaign mode takes only about a minute to complete, and each time it will result in 300 points. After the mission, just save the game in a different file and quit Campaign mode. Load the file for Mission 4 and repeat to get as many points as desired. Note: Make sure to save in the file marked Mission 5 after completing Mission 4. Mission 4 gives you points towards Rachael's CO ranking. Mission 2 is also quick, and is good for getting points for Jake towards his CO ranking.