I would go with #2. Based on what I've read here on the DIS and my own experience, this is how I see that week:
Sunday, Nov 21: Very Busy - NOT an AP blackout date but it is a GAD black out date, so clearly DLR expects it to be very crowded.
Nov 22: Very Busy - Yes, it's a Monday, but many school districts now take all of Thanksgiving week off, so it's a holiday for many
Nov 23: Same as above
Nov 24: Super Busy
Nov 25: Thanksgiving - An AP blackout date. It will be busy but not as bad as the previous days.
Nov 26: Very busy BUT no AP's so that will keep some crowds down
Nov 27: Same as above
Sunday, Nov 28: Very very busy with no blackout dates to keep crowds down
Mon, Nov 29: Somewhat busy with people left over from the holiday - probably the least busy of all the listed days.
Both of your choices have AP blackout dates, but the second choice has more days with the possibility of smaller (comparatively) crowds.
I was there the Monday of Thanksgiving week last year. It was very busy but very doable. I was there from rope drop to almost midnight (we only had one day at DLR) and we did everything we wanted to do.
Either way, you should have plenty have time to do everything you want. Just be prepared for crowds and plan accordingly.
Just as an FYI, the line Small World holiday gets longer, not shorter as the day turns to evening turns to night. That was the longest line we stood in (about 30 min) but it moved along well, and the show on the Small World panels is awesome!