I would go when the Food and Wine Festival is going on. That entire time is ok except Friday nights, Saturday after noon, and Sunday later in the day. DLR guests get into the park one hour early which helps you to beat the people at the rope drop. You can pick up a few rides and be near the fast pass machine to get one. Check refurbs for DLR as DCA is regoing a five year remodeling and an addition of a DVC wing to GC.