I can relate to you because I have a six year old, a three year old (as of yesterday), and a 13 month old that will be 15 mths by the time Christmas comes.
I will be doing as we have had to do for the last 3-6 years. We have a gate I think it's called a supergate that is octagonal shaped and we put it around the tree and don't put any breakables on. One year we put it behind the couch with no decorations down low. Just try different things, depends on how curious and active your toddler is.
As for family activities, find out what is going on in your town, we are going to drive to the mountains to go sledding, drive around and see lights, make some special time like putting the baby down early and having hot coco with the fire on and and watching rented Christmas movies. We live 30 away from Seattle and they always have something going on like having Santa at storytime for the kids. Hope this helps and remember that they remember the little things that you do every year such as buying them each an ornament that is just theirs to put on the tree or making them. One year I got kits at Micheals and did all their handprints to give out to grandparents.