Holding suggestions for Mac & Cheese

I have had lots of people asking for my Mac & Cheese to be served out of my vending trailer. When I was sub-leasing a restaurant it was a regular side on the menu. But it seemed that if I had to hold it for very long the noodles got real rubbery & turned to mush. I have been real hesitant to put it on the trailer for fear of having to waste a bunch of it if it doesn't sell. I know I could cook smaller portions through out the day. A lot of days I am the only one running the trailer so because of being busy it causes timing issues. What suggestions do you have for holding and how are you holding it? Thanks in advance!