There is no such thing as a back-up school. All medical schools are difficult to get into and even with outstanding numbers you are never a sure thing for any school. When med school admissions committees are figuring out who to interview, most schools use a points system (say, 1-100). MCAT and GPA typically only make up about half of the points for this process, meaning that if you don't have outstanding rec letters, a strong and original personal statement, good secondary essays, and relevant and meaningful extracurricular activities you really aren't going to have a shot anywhere regardless of what your MCAT and GPA are. Remember, every year there are applicants with 3.8's and 36's on the MCAT that DON'T get into any med school because they don't have the extracurricular experiences, strong letters/essays, etc etc...to back up those numbers. Along the same lines, every year there are people that have below average numbers that get into "competitive" schools like UCSF, Johns Hopkins, etc etc.
Apply to schools that you WOULD GO TO if accepted. If you know that you would hate living in Boston, don't apply to BU. If you don't want a competitive med school atmosphere, apply to schools that grade P/F. If you aren't interested in research, don't apply to a school that emphasize research (some schools actually require research projects...essentially treat you like a PhD student).
