First, kudos that you are thinking so hard about your application! :-D
My guess is that you should put down in your resume anything that you feel qualifies you for the job in question. I tend to shy away from putting hobbies in, but if they brand you in a way you want to appear for the job in question, I think it could help to add them!
I would say "hiking in the Himalayas" could show that you have: An adventurous spirit, determination, an ability to think "out of the box", a well-balanced life...lots of positive qualities that look good in a graduate student! :-) Whatever brands you as the kind of person that would do well in that job. If you're a home baker, it could show that you: have an experimental streak, are settled and comfortable with yourself, or are a nourishing, supportive person.
I liked the previous answer saying that different qualities will appeal to different professors, and it helps if you know them. But ultimately, be yourself and think about the "fit" between your intrinsic qualities and the job you're applying for, and fit them together.
All the best with finding your position!