Do visit the schools. I feel hopkins’ science programs and under grad science/engineering programs as a whole are at a different level compared to brown (further buttressed by rankings). Having taught brown and jhu graduates in various majors at Stanford as a PH.D. student more recently than some on here in interdisciplinary fields,i would hold the hopkins undergrads in higher regard. There are ample opportunities at hopkins via PURA and open minded professors as well. I personally had a blast at hopkins as did many of my friends who are now at or have graduated from top grad schools like harvard and stanford with competitive fellowships from the schools. You can both have fun and do well at hopkins.