Meatloaf Help

Hi All!
Am planning on making a meatloaf for guests, but need help with my timing. After my guests arrive we are all going for a long walk to look at the Christmas lights. If we are gone for about 1 1/2 hours can I just cook the meatloaf at a lower temperature for that long?

2 lbs–is that enough for 6? I like the crockpot idea, does it hold it’s shape ok?

Thanks so much will try the crockpot. Also, can I put together my macaroni & cheese casserole the day before and not cook it until the next day?