A tensioned fabric structure the size they would need for the parade floats can be put up inside of a month, and be inspected and ready to occupy inside of two. And a prefab steel warehouse doesn't take much longer. They can start on the footings as soon as the blueprints arrive and are approved by the local Building Inspectors, and the slab can be poured and curing while the building parts are shipped.
You clear a large strip of land and pour a slab with a perimeter wall footing and large footings for the support beams, give it a week to set. Then bring in a small crane, put up the tensioned fabric building hoops, stretch the fabric, and clamp the bottom edges of the fabric to steel channels fastened to the concrete.
Or put up the main beams for the steel shelter, then the cross beams, then lay out the steel roof sheeting and screw it down. A well organized crew with all the parts on site and pre-sorted can get football field sized steel buildings up and done inside a week.
Give the electricians a week or two to get lights and plugs for the battery chargers inside, and the fire sprinklers will take another week - all done.
--<< Bruce >>--