I was also a very outdoorsy person before medical school. I got my hopes up by asking this question and looking at threads where people talked about how much free time they had to go skiing and hiking.
The truth is that medical school is like an all-you-can-eat buffet. If you want more, there will always be more to do. There are clubs, research opportunities, studying, leadership, on and on. In my experience, some people are able to turn off the part of them that says, "Just take one more bite, come on. You can do it." Some people are not.
Your free time will also be dependent on your study strategy and how easy you find it to learn the material. Some of my classmates can read a lecture once and they have it mostly memorized. It takes me more than that, and some of my friends even longer. You can't really anticipate what kind of time you'll need until it's happening. And even then, some topics will click in your brain more easily than others.
I guess what I'm trying to say is: sometimes I park really far away from the med school so that I get to spend more time outside.