I just read the first and the last few pages and have to say I am sorry about the situation the OP found themselves in. Yes, the crowds can be scary at times. And yes, it does seem almost insanely crowded when you are trying to get anywhere after something ends (parade, fireworks, closing time). Thats why last night (Friday) DD9 and I decided not to stay to watch the fireworks in the park (and I love to watch them with the music) but to head out early enough to watch them from the parking structure. We parked just one story from the top.
We ended our evening in TL and barely made it on the train in time to get out of the park before showtime. (Don't even ask me about being stuck on Autopia for 10 mins. waiting to get out of our car and how bad the fumes were!

-that can't be healthy) We basically ran to the tram (had to skip getting kettle corn, the line was too long) and got off the tram just after 9:25 (fireworks start). We got up to the 6th level of Mickey and Friends and picked out our spot to watch the fw. Funny thing happened last night-the fw were about 20 mins. late

and since we weren't inside the park we didn't know what was happening. I can't imagine how it was standing on Main St. waiting for them to start.

We saw people sitting down waiting as early as 7:30. DCA closed at 6 for Mickeys ToT and DL got pretty crowded.
We watched the fireworks and after they ended at about 10 p.m. we got to our car quickly and got out of the structure before the crowds starting exiting. In this way we saved being caught in the massive crowd and Main St. as well as being in the crowd waiting for a tram. That's what planning can do for you. Had we stayed in the park to watch the fw we wouldn't have tried to exit the park until at least a 1/2 hr after. Even if we just sat and waited on a bench. It's the best way.
I do agree with others that people do seem to be getting ruder everytime we go. I am constantly amazed at the audacity of some moms. Last week we waited about 1/2 for the nighttime parade to watch me nephew's friend perform. I was saving our spot (for 6 of us) along with my DD9 while my DM and DSis got their AP. Then my nephew took my DD to the bathroom. At this point there were 3 of using saving our spot. A mom and her son pushed my stuff out of the way and sat down. I explained to her that I was saving space for my family. She said "Well, there not here now, are they!" Was she *($#*("#$() kidding me! I explained to her that they were in the bathroom but she just ignored me. This was about 10-15 min. before parade time. Then one of the CMs got all the kids up to play a game of Mickey Says while waiting. I got up to take a few pix of DD playing (the rest of my group spread out to save our remaining spaces) and while watching the game I saw another mom and kid sit down in an open space. The man sitting nearby said "those spaces are for my family. They're playing a game" She said "Well, they're not here now, are they? (I think she must have been related to the rude woman who grabbed our spots.) The man just looked at her. His wife, who was in the street with her kids also turned to look at her and said the same thing. The woman basically ignored her and said to her son "you sit right here on the curb and I'll stand behind you." Like she was doing the other family a favor by only stealing one spot.
Both those incidents really bothered me and just reiterated why I don't like to watch parades at DLR. People are rude and pushy, and most of them only care about their kids. How many times have you (after waiting a long time) had someone try to push their kid in front of you once the parade starts?