Aunt

On the travel thing. i know i did this before going to college as a young adult and it was very broadening. If you can't afford it have him get a job perhaps in a book store or coffee house. He can hang with his friends and save up for something worthwhile. You may be able to met him half way with a few bucks.
Like Music Dad said don't be scared of the punks. I was one of these kids, they don't bite. Try and get to know his friends. Obviously don't embarass him by following him to the coffee house, but perhaps go on another occasion. You might find that some of these adult intellects are really good influences on the boy. Often kids can be a bit snotty and aloof at this age. I think it is because like everything that you experience for the first time, you imagine you are the only one or your family does not get it. I felt like this when I took a summer class on existentialist philosophy when I was about this age. My professor was the smartest guy in the world and i was surrounded by cooler older college students. i felt like my parents were philistines in comparison. In hindsight i was insufferable.
Finally remember that he may be missing his dad. A kid of this age might find it hard to admit this. it sounds like this kid is asserting his independence in pretty healthy ways. Be happy about this