And it's not even like they go from one spot to the next at a time - these are multiple crews of people getting as many areas at once as humanly possible.
When Main Street USA is being done you literally cannot fit any more lift or crane equipment down the entire length of the street.
Universal does have "less" to do than Disney, but they also have to quickly remove all of HHN as well.
If you ever look where you know holiday decor goes in the non-holiday period, look for eye hook in various facades. Those mark where the wreaths, garlands, etc.. go. Those are all done before the night of install.
So the locations of pieces are planned - like two 6ft wreaths, twelve 8ft garlands, etc.. for a building and for months prior people go out and verify mounting equipment is in place and functional, or they install it as needed. Meanwhile others are actually fabricating and repairing pieces.
MK and Epcot both actually get 2 nights of install. MK is pretty much Main Street, entry, toll booths, etc.. on one night and then the rest of the park on the other. Epcot is all about the countries - some can be done in a night, others take both nights. The crews stay in their assigned country until finished and then move to the next one to help out.
Resorts each get one night - but they can be doing like 5 resorts in a single night.
Nearly everything has some go-back time to fix things that broke, didnt fit properly, etc..
