Nothing official has been announced yet, but right now, based on what happened yesterday with WDW's park reservation system, having your GCH reservation should give you priority when DLR's park reservation system opens. (We don't know yet when that will be.) But you will need to have already purchased your park tickets to make those park reservations, Can you call the GCH to ask about this? DLR has not announced when they plan to start reselling tickets. Some authorized vendors were selling tickets as of last week, but I don't know if any of them still are.