<p>All are great schools, with Haverford and Carleton being known as two of the strongest LACs for science generally and Haverford known for cranking out successful med school candidates. Sounds like you want the LAC liberal arts education, which also favors them. </p>
<p>Re research, Duke and Vandy both have medical schools (with Duke’s being among the nation’s best), and so depth of research almost certainly better there. But as I recall both Carleton and Haverford require a research thesis for graduation. So not only are there good research opportunities there (remember this is undergrad, not grad research, and so the focus should be as much on research methods and process as the latest equipment), but Haverford and Carleton force the students to get involved in research. If you are a self starter, then this may not be an issue, but if not you will have to scout out appropriate professors for research at Duke and Vandy. </p>
<p>In addition, the Haverford program with Bryn Mawr is really well established and the schools are just a short distance (ten minute bus ride) from each other). I would not worry about that. Plus, Haverford has a program with UPenn where students can take some classes there too, including in the sciences. </p>
<p>In short, all are great programs, but I would go with Haverford for the above reasons plus in my view the Philadelphia suburbs are by far the best location of the four schools.</p>