Adventure-travel is any activity used as a conduit to observe, share, enjoy, suffer, encounter, or experience that which is outside the boundaries of one's own day-to-day life. You don't have to go to Thailand or Central America to be an adventurer-traveler, but you can. And it's probably better not to have a specific goal, but there are no requirements about that, either. 'Boundaries' is the operative word here; real, implied, or imagined, if your body or mind crosses a boundary, you are doing it.