Another way to beat the rush is to not be in a hurry to leave after Illuminations. After it ends, just stay put for 10 - 15 minutes. It's very pleasant to walk leisurely thru WS without the rush of people. By the time you get to the front, the first mad rrush of people have left from the parking lot and buses. We used to rush to get out, but a long time ago, we decided to take it easy instead. You will get to your resort about the same time without feeling like you have been thru the mill.
On our last trip, in July, we watched from one of the terraced areas on the bridge between France and the UK. The only bad thing about it, was that a large group of the people who were standing right along the fence left before the show was over. As they left, they bumped into people because the lights were still out and they interfered with otherr people's ability to see the rest of the show. So, anyone who is planning to leave early, should pick a spot where they can get out easily without inconveniencing anyone else.