I'm going next week (in park tu/w) and just scrambled to book everything. Planning to tell the kids the morning we wake up to go to the airport

The weather looks amazing (coming from the cold wet PNW).
Any tricks for grabbing an early dinner reservation for Goofy's on Monday... Wondering if cancellations are random or upload at a certain time? Or if I would have better luck calling? I see a 5:10 reservation for 3, but we are 3 + highchair. The earliest reservation for 4 is 7:40. Would be a great way to kick of this surprise trip.