We have lived in Disneys backyard for years and yet our kids LOVE going to Sieverville and Dollywood everytime I mention a trip to Tennessee.
So much fun and a reasonable price to boot.
The tree colors i fall are at their peak usually mid October til about Halloween. After November 1, we have found the trees are mostly bare or brown.
Thanksgiving time is nice except Dollywood closes for 2 or more days per week. Make sure to check the Dollywood site for the schedule. She is always closed on Thanksgiving Day.
The Christmas lights are beautiful and everywhere.
It will likely be chilly, so dress in layers.
Consider buying at least 1 Gold Pass for your family and the rest just get regular Season Passes. This way, the Gold pass will get you free parking as well as a 20% discount on EVERYTHING you buy including food. (you will recoup the cost difference in very short order)
If you buy your passes after a certain date in November of say this year, 2012, the passes will be good to use for all of the next year as well, should you take another trip then too, all your admission would be paid for! Great deal!
Dollywood has fun artisan shops to check out as well. Love watching the guys make glass vases, bowls, ornaments etc.
Shopping on the Parkway is pretty good. Tennessee has an 11% sales tax, so that is pricey, but there is an AWESOME Christmas store that is amazing and has great prices. Plus, if you are from any other state, your purchases are tax free if you have them ship your merchandise to your home address. They ship UPS and I have never had any problems receiving my stuff a couple days after we get home.