We have watched Illuminations from many different spots. Our favourite is across from Germany - there's a spot right by the lake that has a perfect view if you stake it out at least an hour ahead of time. We take turns holding our spot while we go get a snack, wander a nearby gift shop, etc. It's also great for after Illuminations, because you're at the back of the park, and we take our time wandering out so most of the crowds have left by the time we get to the exit and the bus.
Enjoy your trip! I leave in 25 days for a trip with my sister for my birthday and the Food and Wine Festival!