Harvard-Westlake in CA is a feeder school to Stanford just as Exeter and Andover to the major Ivy schools. These schools all have very generous scholarship, and admission is based on aptitude more than family income. In fact, kids from underrepresented groups (blacks/Hispanics/Native Indians) have just as high a chance as white and Asian kids from low-income households. Legacy plays an important role but those that got in from this batch is no more than 16-25%.
I've also always wondered about the ones that are not in the Northeast and how their reputations are. We have one right near our house, Cranbrook Kingswood, that has had some big names go through its halls in the past and even now I know that they attract students from all over the country. There's always articles in our local rag about some of the stuff their students are doing or places they are studying, etc. and it always amazes me. They also list their graduates each year in our paper along with activities they were involved in and where they are headed off to college and I've never seen so many kids from one school going to the Ivies, Stanford, Cal Tech, MIT, Duke, the Service Academies, etc. The lowest ranked schools listed are always a few kids going to Michigan State or Ohio State and I would imagine many of those are probably because they are following in mom/dad's footsteps. If I could afford it, I'd definitely send my daughter there when she's old enough. Sadly, unless her grandpa wants to shell out for it, it's not going to happen on my low level local government bureaucrat salary.