OK, here's a thought. Does it HAVE to be turkey? Why not let them know that it will be a special meal, maybe some family favorites, but not the traditional "turkey dinner with 900 fixings." Save that for Christmas break when you have more time off. Just give thanks for the opportunity for the family to be together and enjoy each other's company. Because you will get to be together and that's the most important part!!
When I was in grad school I only had 2 days off for Thanksgiving and I didn't have the money for a plane ticket home. My sister bought a plane ticket to come and see me. All my roommates were staying at school too, and 1 other roommate had her sister coming to visit. We invited a few other students who were "stuck" there, and we did make a turkey dinner! My grandmother mailed me her stuffing recipe. I woke up at 5 to start the turkey and stuffing. Everyone was asleep and I had the bird in the oven and was back to studying
Other roommates took charge of other parts of the meal. It was a nice day but if my sister hadn't been there, it would have been a very down day for me.
It's not about what you serve for the meal--it's about who you eat the meal with!