I'm a current prepster. The report day will be in the middle of July for a 4-week basic training detail. The school year will begin around the middle of August. Mine started on the 8/12, so it will be around then. Graduation will be sometime in the middle of May. Depending on where you are located depends on when you'll see your family. There is no formal A-Day Parade like the plebes have. The first time I saw my family again was in October for Family Weekend, but if family is close, it could technically be any day of the weekend after the AY starts. Just no overnight leaving unless they have an overnight pass.
The rules vary each year, last year's prepsters had unlimited passes and had a lot more freedoms (wearing civilian clothes in the barracks), but the rules this year are 1 pass a quarter, must be in Cadet Candidate Casual when leaving post/walking around post. If you do well here, you will have the opportunity to earn more passes/ have a gaming device etc. Some benefits though are that all prepsters can have a car, so they can go a bit further than the plebes can during the weekend.