Keep it simple!
It's just a big roast and you don't get awards for being a martyr 
Choose your meat / veg option based on your likes and dislikes. All meat eaters makes life easy - I'd opt for a traditional turkey, not too big and you baste in oil or fat, season then cook for 40 mins per kg at 180 degrees. You can stuff it but add the weight on!
Roast potatoes - Maris pipers, peel and par boil for 5-6 minutes, toss into a pan of hot seasoned oil for 45 mins to an hour shaking a couple of times.
I do mashed swede (use the potato pan) peel cube and boil for 50 mins, mash with salt pepper and plenty of real butter.
Brussels take about 10 minutes to boil.
I cheat and buy lidls frozen cauliflower cheese.
Red cabbage is my favourite, bit more complicated but reheats and freezes well so make ahead. Chop half red cabbage and one red onion, cook for 2-3,mins in a little olive oil, add 2-3 cups boiling water, 1-2 chopped apples, 4tbsp balsamic vinegar, 3 tbsp brown sugar, handful raisins, 2 bay leaves, 6 cloves, a tsp cinnamon, salt and pepper, bring to boil, cover and simmer for an hour, top up liquid if needed. Can do in oven too.
I use gravy granules for use adding any meat juices.
Cranberry orange sauce is a must for me
Heat zest and juice of an orange, 4 cloves, 3tbsp sugar and a packet cranberries (think they are 200g on a medium heat stirring occasionally and they start to pop, keep cooking until desired consistency, (whole vs smooth) and sweeten to taste