Well,
@zogite,
I hope you looked at the Halloween Announcement here on the Camping Board.
It was posted here on 10/22 and went into effect on 10/26. Since the holiday was technically 10/31, that was 9 days in advance.
Today (12/16) is 9 days in advance of the next big holiday you're asking about, of course (the week of Christmas Day December 25). I would expect an announcement but as long as one doesn't come (and I don't recall reading about such an announcement in the past) you might get in. They still could restrict parking (since you don't have an advance reservation for any activity and you're not a FW guest).
You might be able to get in and attend movie night but you may (or may not) need to be creative to get there. But it probably can be done. In the past, for example, they did not restrict PEOPLE from entering the Fort but if FW parking lots were full, they sent CARS over to Wilderness Lodge to park in their big(ger) lot and folks had to ride the bus that runs back and forth between the Fort and WL. But who knows what this year will be like?
Bama Ed
PS - welcome to the DIS Camping Board.
PPS - locals can "gum up the works" when they try to crash the FW pools in summer or suck up the Halloween treats or fill the parking lots (even more than they are). But as long as you are "low impact" and permitted to visit, have fun! Just give yourself plenty of time to get there in case you have to "flex" the plan.