It's about a 15 to 18 day refurb going into the Holiday overlay, from around Labor Day weekend until the second weekend in September. Then about 10 to 12 days refurb coming out of the Holiday overlay, from usually the Tuesday after New Year's until the second weekend in January.
This year the Haunted Mansion Holiday refurbishment dates look like this at Disneyland:
Monday, August 25th until Thursday, September 11th (18 days)
Tuesday, January 7th until Friday, January 17th (10 days)
At Tokyo Disneyland, their Haunted Mansion will be closed to install the Holiday overlay roughly the same time as Anaheim's:
Saturday, August 23rd until Monday, September 7th (16 days)
The toughest part about doing these Holiday overlays at Magic Kingdom Park, either the Haunted Mansion or It's A Small World, is the fact that there are a lot fewer rides at Magic Kingdom compared to Disneyland, especially big E Tickets, and the Magic Kingdom has an overall smaller ride capacity than Disneyland has.
Disneyland can withstand the hit by having a few rides closed, but Magic Kingdom Park can't.
If a holiday overlay were to come to Magic Kingdom, I would think Space Mountain Ghost Galaxy would be reasonable. At Disneyland, Space Mountain is only closed for a couple days on each side of the Halloween themed Ghost Galaxy overlay. It's primarily an overlay done with HD projections and new audio, with only a few real props or set pieces or signage needing to be installed. Ghost Galaxy should be an easy overlay TDO should be looking at, I would think.