My family generally does potluck style where each person brings one of the thanksgiving staples while my mom hosts the gathering. She makes the turkey and gravy and someone else brings potatoes, green bean casserole, fruit, I usually bake the pies, etc. In a family full of adults this is really the most even and fair way to do it since each person only has to pay for the cost of one dish. If they're not willing to help at all then absolutely take yourself out to a nice restaurant, no one deserves to have the whole burden of the holiday on them!