I attended CVW in the spring of my junior year and then was selected for NASS, as well. I did not apply for or attend Girl's State once I found out I had been selected for NASS. Like your son, my school gets out late in June and I could only miss one week. I chose to attend NASS because I wanted to show the Academy that I was very serious in my pursuit of an Appointment and that I would take advantage of every opportunity they offered me. People have said that NASS has no bearing on an application, but your squad leader for the week does write a report on your performance, and a good recommendation could be beneficial. I also wanted the opportunity to take the CFA with a group of people to motivate and push me, rather than alone. I prepared A LOT for the CFA and passed on the first try at NASS. The atmosphere there was great, my squad mates and the detailers were encouraging, and I have no doubts that it improved my score. I would highly recommending completing the CFA at NASS. I was then also able to call the Academy a week or so after I left and have them forward my scores to the other Academies I am applying to. Hope that helps.