I have a few ideas for Christmas

First would be a huge train on the railroad tracks similar to the Polar Express and then you can jump on board when it stops at certain locations for a few min. Inside is a new level where you can buy some stuff (i.e. hot chocolate) and sit on chairs, and there could be a small board at the top that says the next stop.

Second idea is a "quest". We could have a Santa NPC that usually rides the railroad tracks with the sled draisine (in his message when you talk to him in Snow Town railroad tracks) but he is looking for his reindeer. You would have to go around the map to return the reindeers back to him using the horse whistle (however once you reach the cave before Snow Town it will follow you since you need to equip lantern.

These would probably take a really long time to make but I think it would be cool maybe for future Christmases