College Prep Private HS options?

Anyone knowledgeable about US college-prep private high schools? My husband and I adopted three daughters from China when we were already well along in years, and are now itching to relocate with our youngest in tow. DD studies French and Chinese but no Spanish, though I expect she will pick it up if she were immersed in the language (although we are looking for a school that teaches in English). She will be in 9th grade in September. While public schools have definite appeal, she is a workaholic overachiever chomping at the bit for a rigorous college prep education, and it looks like a private school is her best bet.

I will read the schools' websites, possibly make phone calls, and definitely visit sometime in the coming months, but I thought I would ask here for first-hand experiences and ideas. Websites can be deceiving.

Also, if we relocate to CS, we would choose a school in a desirable neighborhood, of course, and choose to rent (and then purchase?) a residence near the school. So a noisy city does not appeal. There are a number of HSs in Guanacaste.....?

Thank you!

The public school system will not provide what you want in regards to education. Plus, they may require proof of residency. The public schools education will not be Internationally accredited .
Possibly, the  CRIA  school may suit you both.   
More choices of better schools are in the San José area.

BTW what do you mean by 'CS'?

You really should visit before you make any definite plans.

Please note that I state twice that my inquiry is about private schools only.

CS was a typo. Sorry for the error. I type CS frequently as shorthand for the Chinese School my daughter attends.  I meant to type CR for "Costa Rica."

I apologize ...but when I read on your post that you mentioned 'public schools have definite appeal' ... I did wonder  why you would consider this option.

Thank you for your note, Kohlerias. After the words "WHILE public schools have definite appeal", I outline why I prefer my daughter attend a private school. I didn't want to sound like a snob who preferred private over public.