Weekend before Thanksgiving?

[Luv Bunnies]

My DH has his heart set on spending his 50th birthday at DL and I'm trying to figure out if we can swing another trip (already planning one for July!). We would fly down on the evening of Friday, November 18, spend the weekend at DL, and fly back on Monday the 21st. I'm wondering if the Thanksgiving crowds will have kicked in by then or will they arrive later in the week? My parents would like to come along and my dad will need an ECV, but is hesitant to go if it's going to be horribly crowded. Any insight/experiences would be appreciated!