Cross country and weightlift?

160 pounds is probably the maximum you want to weigh, 150 pounds would probably be better. High school cross country is 3.1 miles. Training runs are probably 7-8 miles. I would say you probably want to run about 6 miles 3 times a week at a challenging but not too challenging pace. Worry about speed when you start training with the team. Your goal for the summer is to build endurance. I would back off on the Weight training to a maintenance level on the days you do not run, one set 15 rep range. Distance running is about endurance not strength.