There will be a lot of people arriving the Saturday and Sunday before Thanksgiving, with plans to stay the week. It will be a little more crowded in the parks the second half of your trip. Just be sure to make dining ressies as soon as you are eligible to make them (May?) and plan your park visits well – go early, stay late, take advantage of EMH, use your FPs… you will be fine. And you’ll get to see Christmas decorations too!