Going to post a more detailed reply here.
My first semester, I took orgo I and genetics, calc II, and a GE
Second semester, I took orgo II and biochem, a GE, and an elective
Third semester, I took A&P I, cell bio, a GE, and two electives
4th semester, I took A&P II, Physics I, a GE, research lab, and two electives
5th semester, I took Physics II, Orgo lab, a neurobio course (for major), and an elective
6th semester, I took a neurobio course (for major), two GEs, an elective, research lab and three one-credit kinesiology courses that were basically like gym class but for college 🙂
This upcoming semester, I am likely going to take Inorganic chem (I AP'd out of gen chem and just found out that a bunch of schools don't let you count those credits), three electives, and research lab.
Not listed above: heavy involvement in marching band/pep band and other ECs. So yes, all or mostly science and math is definitely doable. I had a few semesters where, aside from one elective, I had all science courses. The two keys are: first, you need to be able to manage your time well, especially with multiple lab courses (Physics II+Organic lab was a bit of a doozy). Know how long it will take you to study and do lab reports, and make a point to budget that time. Second, understand your limits. If you get a month into the semester and feel like you're drowning, go to your professors for help. If you still can't take it, it's better to take a W, take some additional time, and retake the course.
Hope this helped, PM me if you want help/more specifics!