Yes! It is possible to have an American Thanksgiving dinner in Korea. However, it may be a little different than if you were to have it in the United States. For example, it might more expensive or you might have to compromise for one dish you absolutely want to have over another. Though I can tell you there are so many options now in Korea for an American Thanksgiving.
When I first came to Korea 2.5 years ago it was a struggle to have a dinner. As the years have gone on it has gotten a little easier. This year I have had to actually turn down some dinners because I had many options. Now you can order from Craftworks Taphouse, most churches have a dinner, if you know someone on a base you can usually get a turkey, or other foreigner restaurants will have a turkey dinner option. It is interesting to see Korea become more western throughout the years.
Here are some pictures from my 2015 Thanksgiving in Korea.
I forgot to get a picture of the pumpkin pie. This year we picked up a pie from Costco and one from High Street Market. I would have to say that Costco tastes better. The High Street Market one is made with real pumpkin while Costco is more of our normal canned pumpkin. So depending on what kind of pie you want will depend on where you buy it. Pumpkin pie is not readily available unless you go to a foreign market.
The average cost of an American Thanksgiving dinner in Korea is around $30 or 30,000 won. That price has not really gone up too much over the years but it also depends on where you buy your food. There are cheaper places and cheaper options but I have yet to experience them because I always have a great time with my co-workers.