If we are only getting one ride in the DC plot, I hope it turns out to be a thestral carriage ride through the forbidden forest. Have it be a slow moving attraction that anyone can ride. The ride vehicle is perfect since the story says that thestrals are invisible, so Universal can just put these old time carriages on a track that drive themselves. As much as I would love a crazy Flying Ford Anglia ride or a Quidditch coaster, they need an all ages/all height attraction, IMO.