jacki's idea of using a crock pot is a good one. You can cook, travel, and reheat everything. Some of the new crock pots even come with insulated travel bags. Just do a general search for crock pot recipes and you would be surprised all that are out there in cyber space.
Start a new tradition with your meal and give it a creative name - Chicken and Dumplings Travel Afar, Jingle Bell BBQ, Have A Holly Jolly Pot Roast.......a festive bowl of Christmas Carol Chili even sounds good.
Ham seems to be a popular Christmas-time meal. Have you ever tried cooking a ham with Coca Cola added? It gives it a totally different flavor. I even tried using a Dr. Pepper one time and that was good also. If you do not care for ham, you could always do chicken....or a turkey breast. Any of those can be cooked ahead of time and should be easy enough to travel with. Slice, package, and place in a cooler.
As far as your side dishes, just carry the cans and jars with you and heat them up at your mother's house. The smells will make it merrier. Some canned yams can be easily mashed after heated up, add a little bit of cinnamon, butter, honey, and pecans, and you have a nice casserole. There is always green bean casserole which seems to be a good one to make (though I make brocolli casserole instead) - just a few cans of green beans, cream of mushroom soup, and some Durkees Fried Onions and you are good to go. Add a can of corn and a can of cranberry sauce to your list of side dishes.
Ambrosia Fruit Salad could be an easy dessert. A can of mandarin oranges, a can of crushed pineapple, some shredded coconut, minature marshmallows, and either a box of instant vanilla pudding or a container of sour cream to mix it all together after you arrive at your mother's home.
Good luck. Would be interested in hearing how it all goes and what you decided to make and take also.