As much as I love Michigan (disclaimer: committed there), Cornell seems the way to go. I could argue some of your cons for Michigan are not going to be a problem (research + travel) but your cons for Cornell are much less and win out. While you might not end up liking a city location (I'm right there with you on preferring more green spaces), arguably there won't be another time when you can live in NY debt free. NY is pretty fun as student (perhaps not as an adult when reality sets in); Ann Arbor is great for a suburban college town, but it isn't NY in terms of sheer amount of things you can do. NY has a much much greater underserved patient populations, yes it's not right outside your door in the Upper East side, but even here in Ann Arbor, its a 20-ish min commute to outside AA to less affluent neighborhoods (and 40 min to Detroit).
There are absolute peer institutions, but at Cornell, you are debt free, close to family, and have ample access to the types of programs you are invested in with perhaps more easy access than you would at Michigan. Also the PBL learning style might make a huge impact for you if asynchronous lectures are not your thing (it was one of my bigger pros for Michigan). Uncertainty about the city and lifestyle is part of change and imo, lesser concerns 🙂.