We did it last year when he was 1+ and we are doing it again on the 28th of Sept!! Sundays are great since many locals work on Monday, so Sunday=not good day to go!
Tips we learned:
-Take kiddo in a light no-fuss costume that you can turn into pjs at the end of the night. We dressed him in a hand-made (by me!) Lost Boy bunny outfit. I was Wendy!
-Don't push the characters. He liked seeing the princesses (love girls), but other characters were a no-win
-Don't even consider other parks that day. Have babe relax around the hotel, swim, sleep, eat, etc.
-Arrive at 4pm or earlier. That helps get the most out of your party time.
-As much as I hate to say this, the earlier parade is better for LOs.

That way, if they do conk out, at least they saw one parade!
-Fireworks? Not a prob for our kiddo. He loves the fireworks. But if yours freaks, jump on something indoor and long, like HM or pirates. While you might want to see the fireworks, I think not having a screaming terrified kid is better!
-Do take food breaks. Stop at a qs and grab a snack so you can recharge, get a little rest, drink, etc.
-Don't feel shy about using the baby center for changing and nursing. Yes, we still nurse, but only a little. But the rooms are a nice break if you get desperate and only "one thing" will do, and the changing area can't be beat!
-Let them have candy. Seriously, if it's something they can eat safely, let them have it. My kiddo loves chocolate - like his mama! Why torture them?

- If they are runners, get a leash. I know, it sounds so mean, but he loves his leash. It's an Eddie Baurer one with a monkey that is a backpack. It is a lifesaver when all he wants to do is get out of the stroller and run.
- on that note: Get a stroller. A tired 2yr old is a HEAVY 2yr old!!
And have fun! We got many compliments on our costume - I thought no one would get it. But people did, and we had so much fun. My DS has been to Disney so many times - DL at 8mon, WDW at 6/10/11/1yr/2yr, 2Christmas parties and now 2 Halloween parties. He loves it!
If you go on the 28th of Sept, look for us! We will be the Monsters University Greek Council and he will be Mike Wacowski. The rest of the family will be decked out in MU frat/sorority t-shirts