Thank you so much for the great information.For fireworks viewing on Main Street, anywhere from 30 minutes to an hour should give you a great spot. Play it by ear depending on the crowds that day and when you start seeing the street fill up. We usually give it about half an hour and watch somewhere by the arcade. But Mondays are crowded days, so just be aware of where you want to be and when the crowds start getting to that point.
For PTN, that parade route is very long, so finding good viewing spots isn't too hard. If you want to be on the curb or in the front row (there isn't a curb along the entire route), 60-90 minutes should do it, depending on the crowds. Watch when people start holding spots, decide where you want to view, then take your spots. Some areas fill up much faster than other areas, so don't think that the entire route is full just because you see one section looking full. And if you can be in the second or third row, you can find spots with a half hour or, sometimes, even less time.