You will have a great time if you come that time of year. The Holiday decorations go up before Thanksgiving but the crowds are not nearly as huge as December. We do not have a halloween party (we had them several years ago) because of Knott's and Universal pretty much "owning halloween" just as disney "owns Christmas" but we are hoping they will bring it back.
We do have Haunted Mansion turned into "Nightmare Before Christmas" which is NOT TO BE MISSED and Small World gets a complete holiday makeover as well that is truly magical (the only time my hubby will ride it (lol))
the parks are a short walk apart with downtown disney in between--great park hopping! The tickets as far as I know are all park hoppers unless you just buy a one day ticket. There is a special online right now you should look in to:
Get a 5 day park hopper for the price of 3 days.
Offer valid January 8, 2003 through January 5, 2004 with no blockout dates.
You must use your first day prior to jan 5,2004 (or on jan 5) and then you have 13 days from first admission to use the other days. Guests ages 10 and up promotional ticket price is $119 for five days of back and forth admittance for both parks without restriction.
ages 3-9 tickets Park Hopper special offer price is $95.
Offer not valid at Main Entrance ticket booths.
can only be purchased online