When we went last year, we purchased tickets to 2 halloween parties. It was a good thing we did because our first party was overwhelming. The park attendance that day was small and all rides were a walk on. We were disappointed when triple the amount of people showed up for the party! Character photos were important to us and they use up a valuable amount of time. We used regular park time before the party to sit in line for 7 dwarves.We were still 12-20 people into the line and with the dwarves taking frequent potty breaks, it really but into our time. We spent so much time waiting for them that we had horrible seats for the parade and were disappointed about our 1st party night.
My recoomendation for the candy trails: They aren't a huge deal. They are all over the park and we would just walk through them as we made our way through the park . I wouldn't recommend doing them first and wasting time especially if you want character pictures.
The 2nd party we issued a better plan of attack. We were first in line for Mickey and Minnie and killed over an hr of regular park time to wait for them. We did the candy trails as wel traveled through the park, and I believe Pooh and friend's meet and greet opened a half hour later so we waited for them on Main Street.We then sat at the train station on Main street and waited for the fireworks and parade, which were back to back (kinda) Again we wasted something close to an hour of time waiting but it was well worth having great seats for both events. It wasn't much of a waste. I saved our seats as hubby ran to grab us dinner and then he saved the seats while i grabbed some halloween souvineers. Also, If you see something halloween party themed, buy it because they only have stuff with MNSSHP on it suring the actual party. Hope that helps! Have fun!