Extracurriculars are organized things you take part in. Usually that means they are school associated, but you might include volunteer work at a church or tutoring at an elementary school in that. Also, “extracurricular” means that they are also outside of the curriculum, i.e. not in class.
So travel might be an interest (and one that can teach you a lot and make you more cultured), but it is probably not an extracurricular unless it is associated with a particular school club.
As for hours and weeks, you approximate. Generally you want to be as favorable towards yourself as possible without being dishonest if you are estimating. So if you go between 1-3 hrs per week, 3 weeks per month, then over 6 months you’d probably say “2 hrs per week and 18 weeks.” Don’t forget prep time for an extracurricular (do marching band on the side? add in practice time at home, etc).
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