Even if there is a gate for guests with early dining reservations (I've heard mixed reports about this), it would probably only be for guests with reservations inside DCA. Storytellers is not inside DCA. It's inside the hotel and does not require entrance into DCA to get to it. So I would not count on being able to use the DCA entrance to get to Storytellers at that point. Besides at that point, the ticket lines to get into DCA will probably be fairly long and slow, so you could probably walk through the DTD entrance to GCH much faster.