Ok well if your looking for a seat for the fireworks.. I suggest staking out a spot an hour or so before the fireworks in front of the castle (Make sure the hub where the statue of Walt and Mickey is, is not in front of you. Make sure its behind you). With all the effects of the show, you will see it all with a front of the castle view and you can get some amazing pictures. It makes your entire experience well worth the wait.
As for the parades, it ultimately depends on which show your catching. If there is only 1 parade during the day, the route starts at the ride Its A Small World in Fantasyland. I would suggest getting a seat near there so you will be the first to see the parade, and the first to leave to head towards rides. This will save you a headache of longer lineups at your fav rides.
If there are 2 parades during the day, and you catch the 2nd parade, the route starts down at the front of Main Street by the entrance. I would sit down that way for the 2nd showing of the parades.
*Either way, for the parades make sure you sit down a half hour or so before the parade begins. People find seats very early and if you want a side walk seat then you gotta get your butt in gear and find one early.