We have 5-day base tickets and staying for 7 nights. We don't do parks on Saturdays (too busy), and likely doing a Christmas party / After hours during the week. So that leaves us with an extra "day". That's why I was thinking of using a day on arrival knowing how hard it is get all of the headliner rides done at HS in one attempt.
Just thinking about this out loud...and sorry this is a long post but I find this type of trip planning interesting.
You will be down starting the sunday after thanksgiving for 7 nights.
Nov 27th - sunday, partial evening in a park possibly?
28th - monday, park day 1
29th - tuesday, park day 2
30th - wednesday, park day 3
Dec 1st - thursday, park day 4
2nd - friday, park day 5
3rd - saturday - you don't go to parks on a saturday?
4th - sunday - fly out.
If this above is really the situation based on what you said, why aren't you flying back saturday? Flight prices? If you wanted a break during your trip I would honestly put it sometime in the middle of the week. Also if you can get a christmas party event, just take the morning/early afternoon off that day and go only in for the event itself, then use the 5th park day on saturday, otherwise you're somewhat wasting your full day ticket by combining it with the expensive christmas party, which includes admission.
Then your trip might look like this:
Nov 27th - sunday, partial evening in a park possibly?
28th - monday, park day 1
29th - tuesday, park day 2
30th - wednesday, park day 3
Dec 1st - thursday, rest at the resort and christmas party in MK
2nd - friday, park day 4
3rd - saturday - park day 5
4th - sunday - fly out.
If you cannot get into an after hours party, i would seriously consider getting an extra 6th park day in there for Saturday to "mop up" any unfinished business you might have at MK or HS. I used to book like this when free dining was a thing, for 5+ people, the dining was more exensive for large groups than the hotel room was, and number of meals was based on the number of nights. But for that free dining trip you had to book the saturday before thanksgiving or earlier.