The last 3 years I've gone to Chiangmai for Thanksgiving and Christmas meals. Once at Chiangmai smokehouse for their thanksgiving buffet. The rest at The Dukes. Dukes switched the last 2 years from a buffet to a set meal service. Still large portions though.
4 years ago I went to Bourbon Street Restaurant in Bangkok for their Thanksgiving and Christmas buffet meals.
The year before that we did Thanksgiving at home. But a frozen Turkey costs over 3,000 baht. So I figure why not spend that and let someone else do all the work.
I've considered trying some of the hotel holiday meals but they are quite abit more expensive.