So I'm a Mayo student and originally not from the midwest/from a much bigger city and I can tell you that you will for sure be able to go home/travel in general much more often if you come to Mayo. First off there is actually an airport in Rochester (it's small tho) and there is also the Minneapolis-St. Paul airport (not small) which is only an hour and 15 min drive away. How I know you will have more time to go home/travel at Mayo is because we have selectives, so you get between 1-4 weeks off during selectives that are after each block. I have friends at different med schools and none of them have the freedom we do thanks to selectives and Mayo's generous funding. You can get funding for up to 3 trips per year for selectives from the med school, plus it's very easy to get additional funding for travel if you do research and go to a conference; I've had multiple trips covered through department funding at Mayo and have gone to conferences all over the country. In 3rd and 4th year you also have the option to do rotations at Mayo's hospital in Phoenix, AZ (not too far from SoCal) and/or Jacksonville, FL. If you choose to do rotations at another Mayo campus they hook you up (housing, rental car, stipend).
I disagree that you'll have more opportunities simply by being in NYC. You will have endless opportunities at Columbia or Mayo. It's more about fit; where you would prefer to live and which school you think you will be happier at (what
LizzyM and Goro said), but it's not like you won't have as many opportunities at Mayo as you would at Columbia. Also Mayo has a lot more than just a good faculty:student ratio. There is a reason why Mayo Clinic, in this tiny city in MN, is ranked the best hospital in the country with people who come here from all over the world. There are only like 100k people who live in Rochester yet Mayo had 1.3 million people come here for care last year from all 50 states and over 150 countries. Mayo also has the oldest and largest residency training program and around 5k physicians on staff. This still boggles my mind because other hospitals this size are in much larger cities.
FWIW most of my classmates aren't from MN and didn't know anyone before coming here either. You will make friends quickly if you come to Mayo. Classes are super tight because there are only ~45-50 people per class and you spend a lot of time together. There are a lot of people from CA in my class too and they don't love the MN winters, but they deal. Have yet to meet anyone who doesn't think Mayo is worth it. The worst months are Dec-Feb and there's like 5 weeks off for selectives during those months when you could go home or go to AZ or FL campuses. When you get to 3rd and 4th year it's also very common for people (especially those from states that don't really do winter) to do rotations in AZ or FL during winter months.
Good luck and congrats on your acceptances. You can't go wrong either way! Let me know if you have other questions about Mayo