October has gotten more and more crowded each year. Check past and predicted crowd calendars and plan accordingly.
I've done most of my trips in October (though went the first week of December 2016 as October had gotten too busy for us). My tips for October trips:
1) When visiting Epcot for the F&W festival, avoid going Friday afternoon through Sunday. Our party had great times at F&W by going to Epcot during the week (Tue-Thur was best) to sample the booth offerings. After one miserable Saturday at Epcot during F&W, we only go on the weekend as early as possible and to go to very specific booths...or go late for an ADR (with a visit to a F&W booth for a drink or dessert).
2) Ask yourself before you go to MNNSHP if you are there to enjoy the rides more or the events (such as parades). If you want quality ride time, skip the early parade and shows and hit the rides. The crowd for the first parade is HUGE and by skipping it, you can ride ride ride, take a rest during the later parade or shows, then ride some more. Crowds for rides early in the party are light and get very busy after the first parade. This has been the best strategy for my family (but we go to MNNSHP because we love walking onto rides that we usually have to wait for). That said, the MNNSHP parade and shows are fantastic and worth seeing, so if that's your main reason for going, just go see what you want to see...my family takes in later events to rest. Trick or Treating during the party (in our experience) gets better closer to closing time. More than one visit, the trick or treating stops had barrels so full of candy so close to midnight that the CMs were giving out handfuls to everyone, especially kids (one called mine back four years ago and said "WAIT! I HAVE MORE!" before giving them three more double handfuls of chocolate). My kids were in in awe and still talk about it.
3) October is 'mild' for weather in Florida but can still get very hot and very humid. It sometimes rains, hard, though not as much as in summer. Planning midday events inside (ADRs, rides, hotel naps) are great even though you are visiting in 'fall'.