We like to have an early dinner at party nights - seated before 5:00PM. In MK we like Crystal Palace, Liberty Tree Tavern, and the Plaza. We don't care for Tony's Town Square at all.
You could also eat at a monorail resort. Some of our favs are Ohana, Kona, 1900 Park Faire and The Grand Floridian Cafe.
I wouldn't choose "big" restaurants like Cali Grill, Narcoosees, Citricos, or CRT for party night, but that's just me