My personal preference does not maximize park or party time (and will probably go against a lot of advice on this thread), but we don’t usually head to MNSSHP until 6:30-7. Especially for an August party... I want that sun to GO DOWN!
We usually plan a good dinner at the resort, or somewhere close like CR, then head to the party. If we were going to be in the park 4-7, we’d do a longer table service meal and not necessarily rides (or get in line for any character meets). I made the mistake a few times of not eating a proper dinner before-hand, so now we make it a point to make sure we’ve had a good meal and primed to make it all night. My kids are currently 8 and 4 (have been 1-8 in MNSSHP trips) and they just can’t go 4-12 if it’s really hot, so we dial things back on purpose.
But again, it’s more about any personal priorities during that 4-7 time, lots of valid options.
Hope you enjoy your first MNSSHP! You’ll get lots of quality opinions and strategies on this thread.