Based on Diagon and such, I'd get to the park as early as possible. On the 13 either stay on property or park somewhere you can get to the resort entry point next to Margaritaville. They'll likely open the gates to CityWalk at 6:30am too, so high tail it to the IoA entrance and stake it out till open. I imagine they'll open the gates early and run some rides (Hulk, FJ, etc) early to draw some crowds away from Hagrid. If they do it like Diagon they'll have sections of Hogsmeade set up for the opening event: a left corral, a center corral, and a right corral. One will fill then the next then the other. At open they'll let in the first corral to the ride then once that group has entered they'll let in the second. Anyone not wishing to ride will be diverted on the bypass bridge.