Here's a link to a calendar that lists all the park hours from November 2007. It even lists parade times and firework times, too. Looks like MK was open until midnight every day...1am on Thanksgiving. Epcot had their regular hours. The Studios was open until 8pm, as was AK.
Walt Disney World Theme Park Park Hours - November 2007
At least we have this as a guide.......
BTW, has anyone ever been to Le Cellier on Thanksgiving? Last year, it says they offered a limited menu, in addition to Holiday offerings.