@allthingstesla We asked about research opportunities on our Brown tour (daughter is interested in neuroscience) and were assured that they are available as early as freshman year, but I would do your due diligence and ask. Make contact with some professors at both schools - say you are have been admitted and that you are honing in on a final decision and are interested in undergraduate research. See how responsive they are. Do they email back promptly? Does the response seem perfunctory or more engaged? Etc.
Also, if you decide to back away from pre-med, what other majors interest you. Check out some departments and see what they look like.
Overall, I think that Brown is higher caliber than JHU. For pre-med specifically, probably not, if you assume that the ranking of the medical school carries over to undergraduate training. The public health program at JHU also is superb. As I’m sure you’ve been told, getting into med school is primarily a matter of GPA and MCAT scores and the reputation of your degree-granting institution is somewhat secondary. Would JHU give you a bit of an edge over directional state, all else being equal? Certainly. Would the difference between Brown and JHU be meaningful if you get to that point? I can’t say for sure, but I doubt it.
Again, you have two wonderful choices in front of you. Either will provide an excellent education.