My kids (16&11) go to both parks by themselves. They love the independence. Last trip though, DD11 got in an arguement and embarassed DS16. They returned to PBH and DS16 was as upset as I've ever seen him that his little sister was so defiant (welcome to my world, son!). At that age I think they are OK in the park especially when you are staying on site. I usually go with them at park opening and when the crowds build at 11 or 12 I tell them I'm going back to the hotel and take a nap. They usually want to stay but return to the hotel before I have to go looking for them or we set a time/place to meet.
Pteranadon Flyers is similar to a ski lift that circles Jurassic Park overhead. You get a good view of the park but its not real thrilling. It is so slow loading that IOA puts a (height or age?) limit requirement for one of the 2 passengers that the "bird" holds. In the morning they let adults ride unattended by little ones. When the queue builds they start enforcing the requirement. It is a good ride to experience since it will most likely be the next to be discontinued. Both WDW and Busch have stopped their sky trams (It has to do with how they could be evacuated if necessary).
CityWalk's HRC is the largest in the World and I recommend going at 11 when they open. They encourage you to walk around and check the place out while they cook. Its easier or less embarassing for teens at opening when the restaurant is empty. I have found their cheeseburgers (with sauteed onions and mushrooms) to be the best at any of the full serve restaurants on site followed closely by Jimmy Buffet's Cheeseburger in Paradise at Margaritaville. My kids also like the pizzas at Mythos which is best restaurant in the parks (IOA).
You'll have to read up or ask questions about the rides. There are some that teens might want to skip like Barney or Nickelodeon Studios.
That time of year the weather is unpredictable. It could be 40 or 80. You might plan a "water ride" day where you pool hop the resorts and hit Ripsaw Falls and the Bilge Rat Barges. This is usually best done in the warmth of the early afternoon. The pool at HRH should be warm and close enough to do most anytime you are there.