To guide you properly, inform if you are a student or parent and if student which grade you are currently.
There are 2 sections in CC and specific threads have tons of information. But if you are a student, would recommend to focus on your studies and ask parent to review and share the findings to save your time.
Very briefly to address few myths. You get in to good residency because of what you did in your MD in the lowest ranked college and not because of attending prestigious college. There is nothing called best BS/MD programs, since each program has its own pros and cons. Would recommend when time comes apply to few BS/MD and few good UG colleges of your interest. No need to rush to do it only in 6 years BS/MD programs or desperation to do it any where at any cost at HS stage like apply to BS/DO, Caribbean, International, for profit MD schools etc
95% of students do MD via regular route and with gap years due to personal or forced situations.