You spend the whole game looking for information on The Wild Hunt but is there actually a quest including it at some point? I ask because its probably one of the coolest pieces of lore in this game and also there is a book that is also a quest item, but I didn't do anything except gather information in 2 playthroughs.
Nope, no quest that allows you to actually participate or chase the Spectral Riders.
But despite that there is pretty heavy hinting that Witcher 3 will have to deal with it in some way. Though i think the Nilfgaard invasion will be the main quest plot the Wild Hunt will also be a pretty big deal but not on the scale as an invading Nilfgaard.