We have found Thanksgiving the last few years seem busier then xmas, but that probably had to do with xmas in the middle of the week. The parks will probably be very busy, so my advice is go early then leave around lunch for your resort. Take a midday break with a nap or swim at the resort then return for dinner and more fun in the parks.
As for the weather who knows in Florida every year is different. One year we went it was beautiful hi 70s and cooled down in the evening. But one good rain storm and the temperatures will drop. Best to be prepared for either type of weather we always plan layers so we can go either way.
Pretty much all the disney restaurants offer the traditional Thanks dinner, with the exception of the countries in Epcot. LTT will be the most popular so I would suggest Yacht St, Brown Derby, Artist Pt or Boatwrights. You definitely want to make a PS at the 90 days out mark, as many enjoy Thanks at WDW. You will be required to put a CC on it just in case you dont show up. You may want to check www.wdwig.com in the coming weeks as she often post the specific menu for that day, but dont wait on the PS.
The other perk is that you will start seeing many of the xmas decorations already up. Disney usually starts most of the xmas activities the day after Thanksgiving. I think the first Candlelight Procession is the 29th so you might think about reserving that pkg one night. It is a great way to get you in the holiday mood.
