When we first started going to the F&W Festival, we would go the week before Thanksgiving, and I found it to be a great time to go--the parks were not that crowded, and most of the Christmas decorations were up.
Due to work schedules, for the last two (maybe three) years, we have gradually moved our fall vacation back (this year we are going the first week of October) so I can't contribute up-to-date information, but I'm sure you'll have a great time--you will get to enjoy the decorations, and the F&W Fest, and the weather is usually dry.
We've already decided that next year we are returning to the third week of November for our F&W trip!