How can I make ahead and bring to a pitch in?

I love that plan---the foil and possibly the burners. Then I won't be taking up the oven space for the hostess. Thank you all so much for your interest in my project! Love, Susan

Thanks for your note, Susan! If the gathering you're bringing it to isn't far away, then I'd heat it thoroughly in your oven at home, cover it with foil and bring it -- it should hold its heat for at least 30 minutes covered. Alternatively, if there is a stove on site, you could place the covered baking sheet across two burners and keep the mac and cheese warm over low heat. This approach is a little riskier but if you keep a close eye and turn the stove burners on and off as needed, you can warm it without burning.

Thank you! I was thinking of something else and am now back to going with my original thought of the Baking Sheet Macaroni. Your answer was just in time. I'll let you know how it goes!

Hi Susan! Looks like Nancy shared some super helpful advice below, but just wanted to say that we think your idea to make in advance and then keep warm at the event sounds like a good one, and if you can avoid that bowl, at least at first, we would (to preserve the 50:50 crispy-soft ratio!). Hope it's a huge hit—let us know how it goes!

Thank you so much for your rapid reply.

Hmm, I was hoping to use this as a side dish---not an appetizer. I do have the Salton Hot Tray I could bring. Make the recipe as it says just before I leave home, put it in a serving dish and keep it warm on the hot tray? Would it lose something if put in a bowl after the fact?
Thank you for your rapid response and yes, a pitch in is a pot luck :)

Is a pitch-in like a pot luck?
Here's one possible approach.
Amanda Hesser in writing the recipe increased the crunch factor in mac & cheese from 20% to 50%.
As you don't have an oven at the event, maybe take it further (to 80 or 100%) and make this a crispy roasted snack to eat with fingers, not an appetizer dish for forks?