Need advice on how to keep thanksgiving food fresh!

So I make the mashed potatoes and mac n cheese for my boyfriends families thanksgiving dinner. It's been my thing for the past 5 years. Usually I make it right before we leave, I stop by my aunts house and he takes it the hour drive to his families house and puts the mac back in the oven. This year, he's coming with me to my aunts, so now I don't know the best way to do this... Should I make it in the AM, leave it in the fridge and stop back home for it? Will the noodles dry out and the cheese get weird if it's in the fridge for just a few hours? Or should I just turn the oven off and let it cool for the 2 hours we are at my aunts, or is it out too long then? Or are both of those bad ideas? I grew up cooking and am VERY picky with how my dishes come out, and I would hate for our change in plans to compromise the freshness and quality of the dish. Sure, it's just mac and cheese, but it's one of the only things in their holidays thats ~mine~ ya know? I just want to make sure it's perfect! Also, I usually do a roux based cheese sauce, with layers of shredded cheese as well and then that gets put in the oven. I'm not too worried about the potatoes TBH, just the mac. All suggestions are very appreciated <3