If you made a commitment to concentrate on the 200m and 400m, train only to compete in the 200m, 400m and occasionally the 800m. Do not do anything else after track practice because you are training for the long sprint and any other training will interfere.
When track season is over, then you can make another commitment to train for cross country. Let us know and we will help you at that time.
Remember, you are a sprinter now.
Coach Payan
www.CoachesEducation.com