Travel (not considering finances):
Are we talking extended periods or like a 2 week vacation?
Certainly you don’t need to spend every day of your summer/winter breaks in college doing pre-med stuff (especially winter break - only 1 winter break did I do any sort of work). The summer before medical school is completely open.
As a med student, you can similarly travel during winter break and a short vacation during sumer between M1 and M2. After M2, depending on how your medical school is set up and how much time you need to study for USMLE Step 1 you could have a summer vacation as little as one weekend and as much as 6 weeks. Once M3 starts you should get a few weeks of vacation throughout the year. The end of M4 is another prime window where you’ll easily have 1 month to travel.
After med school, the summer before residency is prime travel time. Then residency vacations are going to depend on your program/how they handle it. Usually when my friends have vacation time they travel.
If they are important to you, you’ll find a way.