We've thought about this issue, too. One thing is that the merit scholarships for some of these only cover half the tuition. One school I looked into cost $45K/year, so half is still hefty, especially with college not too far away. Even so, in desperation I told DS13 that we'd be willing to do it. But he's not. DH said DS probably has a better chance getting into whatever college he wants if he stays here, goes to public, Title I (free lunch school), because of colleges wanting geographic diversity. Guess the bottom line for us is that DS doesn't want to do it.
I like what Lorel said about early college & PG. With Ghost, he's really ready for college academically, so you need somewhere safe to keep him while he grows up. Have you considered/can you negotiate Stanford online HS (lower price than boarding schools, lots of advance courses to choose from) mixed in with neighborhood HS? For instance, in our state, we have several HS graduation requirements like PE, Health, State History, etc. that they can do freshman year; then it'd be neat to do a hybrid where some classes are instructors at school, mixed with more advanced courses from Stanford. That way he can progress in math, take APs early on, but still be part of the school to participate in clubs, sports, etc.
My DS13 may be underchallenged, but he's learning coping skills and some content. Plus he has made his own challenges by joining activities that has him absent 2-3 days/wk, so he's always in catch-up/make-up mode. About 15 more school days till we can say he survived freshman year. I've been assured that sophomore year it improves (more ability grouping into the honors/AP classes).
One young lady I spoke to who went to boarding school for a couple years came back here to finish HS. She is very very bright, but could not suffer through public school after she had been there, dropped out, got her GED & went on to college. She eventually got a Fullbright and is now in law school. Don't start off at boarding school and plan to finish back at home--if anything, do it the other way around.
