I had a great time! I definitely learned a lot, and I came home more confidant than ever that I was making the right choice by choosing to apply to USAFA! The altitude was the part that impacted me the worst; I came straight from the USNA's summer seminar, and I am from Florida, where the altitude of both is 0 feet. I got out there three days early, and I still ended up getting altitude sickness for half of the seminar.
The most fun part was Doolie for a Day, where you are treated like a doolie for the majority of the day. I'll let you experience it on your own though
I would definitely try to go earlier, to help get acclimated to the altitude, but also to do some sightseeing. Colorado Springs is BEAUTIFUL. The mountains were amazing, especially being from Florida where the highest thing in sight is a water tower. I would spend a day at the Garden of the Gods, or maybe take a trip up to Pike's Peak, or go the Cheyenne Zoo, or to Seven Falls. There's so many outdoor activities to do, it was amazing.
All in all, the summer seminar is a chance for you to get oriented with the Academy lifestyle, and to see if it is something you could see yourself doing. It is basically a week-long tour, and you will walk away knowing if you want to go to the Academy or not. While I walked away more confidant than ever that I wanted to be there, one girl in my element told all of us that she hated USAFA and would certainly not be applying next year.
Have fun!