Hi Hannah,
Congratulations. NAPS is a terrific program. My son (NAPS 07) took classes much like USNA - Calculus, Physics, Chem, English - plus professional knowledge, PT, etc. Classes are streamed in three levels (I forget the correct NAPS terms, but it's kind of remedial/standard/advanced, based on placement tests).
Can't recall precise numbers re: transitioning to USNA. Son's class began w/ something like 230, and 200 went on to USNA. The majority who didn't, left on their own, realizing military life wasn't for them. You've probably heard the NAPS expression "2.0 and go." Pass everything, keep out of trouble, get a 2.0 GPA, and you're good to go to USNA.
What else? NAPSters wear uniforms, get lots of military training from a USMC DI my son still idolizes, and have many opportunities for sports and activities. NAPS has many, though not all, of USNA's NCAA sports. I visited NAPS during "little Army/Navy" weekend, as they call football against USMA Prep -- lots of spirit and excitement.
Newport is a very active base w/ all sorts of training programs going on (senior enlisted, professionals like physicians and attorneys getting their military training, and of course the Naval War College). You'll see lots of active duty Navy at meals, in the Exchange, and elsewhere on the base.
Though the base isn't very far from the town of Newport, it's more than a walk. Parents love Newport, though it can be costly. It's small, and the NAPSters I knew were a little tired of it by the time graduation rolled around. I forget how long it is until weekend liberty begins, but my son and his friends liked to go to Providence for shopping, movies, etc.
Son felt academics were pretty rigorous. He did well and is doing well in USNA academics so far, validating Chemistry, taking a 400 level course as a 3/C, good class rank. He felt as if anyone NAPS accepted could succeed if they wanted to -- which is not to say it's easy, just doable. Extra help is always available. Faculty wants you to succeed.
As a 3/C, my son's two closest friends are still NAPSters, one a prior enlisted Marine. He would say the most valuable and rewarding part of his experience in Newport was getting to know prior enlisted NAPSters. NAPS gave him a real leg-up in plebe summer, and he learned a lot about military careers in briefings by various experts. His graduation speaker was Col. John Ripley, a USMC legend who passed away last year and was buried with highest honors @ USNA. Exposure to the history, traditions and power of the military prior to I-Day @ the Academy seemed to make that day less intimidating for him, and his NAPS friends. Not their mothers, though! When the F-18s practically scraped the roof of Bancroft to welcome assembled plebes into the real deal, I dissolved. Tell your parents to bring tissues to everything related to your education, starting right now.
Hope this helps. Pls let me know if I can answer questions.
I suspect there's a former NAPSter out there who will gladly correct my mistakes and memory lapses.
Again, congratulations. Start running now!
Thanks in advance for the information. 
