A short day of walking for me is ~4km, just because the site where I work is large and I park and work on opposite ends.
But in my spare time I used to do a lot of XC skiing. I took last winter off to ride my new fat bike, though. I also like to swim, although I do more floating than swimming, and almost always as a cooldown post- or mid-ride. So to answer the question "what else do you do for exercise", "NOTHING"