Hey there, Angie!
Welcome back to planDisney! We're so happy you've dropped by, and are planning another visit to Walt Disney World. Fall is such a wonderful time to visit! Let's talk about the practically perfect way to spend your evening at Mickey's Not So Scary Halloween Party (MNSSHP).
When you purchase an event ticket to attend MNSSHP, as you mentioned you can actually gain entry to Magic Kingdom as early as 4:00 pm that day. So although the event doesn't officially get started until 7:00 pm, you can absolutely make a dining reservation inside the park for any time after 4:00 pm. I'd leave yourself around 20-30 minutes to get from the park entrance to
The Plaza Restaurant in time for check-in. What an excellent way to kick off your evening of fun!
You'll have to wait until 60 days prior to your arrival date before you can make your
advance dining reservation. Mark your calendar as a reminder! As long as you do so when your eligibility first opens up, you shouldn't have trouble securing an early evening dining time at The Plaza.
I hope this helps answer your question, Angie. Have a wonderful time at the Most Magical Place on Earth!
Sending pixie dust,
Tami