You are right on the money to look at academic rigor. Go to the school that is the least academically competitive. I'm from New York so I don't have all the details, but I learned the hard way that obtaining the highest grades possible is the most important thing and just wanted to say your 'major point' is spot on. I wanted to be a doctor but wanted to study engineering as an undergrad while completing pre-med requirements. I went to Cornell's school of Engineering and wow, major mistake. Loved the experience and had a world class education but it definitely made my path to medical school WAY harder. In each class only X number of students (typically anyone 1-1.5 standard dev's above the mean) can get an A and when all of the kids in the class scored 780 or above on SAT math, there's a lot of really bright kids getting low B's to C's and even D's. Some of those classes brought my GPA down significantly and that eliminated me from some medical schools while some of my peers at SUNY schools were getting interview invites because they could cruise to easy A's in their math and physics courses without much effort because ... it's just infinitely easier to get an A at a SUNY school. I thought med school adcoms would realize that my program difficulty/rigor would compensate for a comparatively lower GPA than someone who came from a state-school-or-similar school, but this was not the case. I was viewed as having a lower GPA, and that's that.
I don't mean this to come off as some sort of snob, and if it does, I sincerely apologize. That's not my intent. My point is that if your goal is to go to medical school, ask current students or alums and figure out which school will allow for you to obtain the highest grades. All the other stuff is nice... EC's, groups, opportunities, research, etc... but those are secondary and I'm sure all of them are stellar in those regards. Med school admissions has become increasingly 'holistic,' sure, but don't be mistaken... your grades and MCAT are by and large the most important factors you have control over.