I love Thanksgiving best of almost all the holidays. There is no added pressure of gift giving, just a time for friends and families to come together for some gratitude and bonding.
The best advise that I can give about this Day, is to accentuate the positive aspect of each and every person and relation in the gathering.
Most common folk don't even consider a Caterer on this event, but prefer to cook family recipes that are tried and true, and part of everyone's expectations of what fond recollections of childhood will emerge through the familiar flavor of Grand's Gravy or Aunt Mables sweet potatoes.
Many small Catering companies will be happy to follow family recipes. I once catered a wedding of over 200 people and several of the dishes were family favorites. Roasted Salsa was one, and a corn dish the other.
The guests devoured them while claiming the authenticity of the flavor.