From last years experience......
They provide bags, but if you are serious about trick-or-treating or have little kids they get full and heavy fast, so we had brought other bags (canvas type) to dump our heavy trick-n-treatin bags into.
Get any apples/carrots you want early on, they go FAST, so don't pass on them and expect them to be there later or at the next one...
Lines are long in the beginning and then clear out a bit as the night goes on, but then the apples are gone too.
In the Redwood trails loop you can bring strollers and they have 3-4 stations.
Mickey and Minnie were doing picures together (see sigy pic) and that is VERY rare, usually it's one or the other. I had heard the line gets LONG for those, so we were in the park at rope drop and high tailed it over to Mickey and Minnie pictures first thing, we waited for like 3-4 other people to take their pictures.
Restaurants will probably only be open for an hour or two, so if you want dinner, make sure you get it when something is open.
The kids craft stations were really neat, make time for those if you have kids. Also the dance areas there are some characters dancing around, great interaction rather than just a picture and autograph.
This may be because we went on Halloween night, but they ran out of candy towards the end, but stations that were getting refills were throwing double fistfuls of candy in our bag (big score on Redwood trails last year, but I think it was a luck thing).
At the end of the night all the characters do a little "parade" from right by the first aid station to the front plaza, dancing along saying goodbye. It was fun to see ALL the characters we had seen all night long in one place.
Hope this helps!