I've been going to Disney on Thanksgiving and staying off site at our timeshare for the last 10 years. The only park we've encountered a closing on was MK, and that's not every time. That being said, we haven't gone park to park each time checking. We made sure we got to our park early in the day and stayed so we could eat where we had our ADR. We have shown up on Thanksgiving evening after having our dinner at our timeshare and gotten into MK. The day I'm most concerned about is NYE, because I've seen multiple parks shut down at the same time. However, I still wouldn't risk my Thanksgiving plans and would be at the park well in advance, celebrating the holiday. MK is typically the most popular on Thanksgiving, and AK the least. This year we're headed for the Studios and Prime Time.