Okay here are a couple prep schools that are near skiing that i can think of off the top of my head.
Holderness School- Near waterville valley and loon. has one of the best race programs in NH as well as offers a freestyle program. i believe the martini brothers went there.
New Hampton School- They offer a great USSA/FIS racing program whil their school team is just alright. if you wan to race i would go here or holderness. thier freestyle program is up and coming, but idk where they actually ski.
Kimball Union- i went here and ther race program is alright, but they are improving it. kinda... there is a freestyle team, but it is only in its second year. if you want to be loved by this school just play hockey or laccross ha. they ski at whaleback.
Proctor Academy- their race program is again a lot like new hampton and holderness cus they have a good USSA/FIS team and then an alright school team. idk about freestyle here, but they are near mount sunapee and have their own ski area basically on campus. look up blackwater ski area to learn a lil about that.
Gould Academy- Probably one of the best private ski schools out there. it is far away from everything cus its way up there in maine, but during the winter you will be able to ski everyday just like the kid above said.
those are the private schools off the top of my head that are relativley near skiing. it might be hard to balance a good education and good skiing though. anyone can feel free to comment on what i said