Employ a contract painting company to repaint a large room in a gallery.
This should be a real job rather than have any element of artifice, so the team will arrive on site with all the equipment required for the project - trestles, boards, rollers, paint trays, paint, brushes, ladders, dustsheets, kettle, radio, you get the idea.
The show opens the day the team arrive and start the job, and closes the day it’s completed.