Need help for a Yellowstone trip

I am going on a snowcoach tour of Yellowstone in a few weeks. I have a D3200 and wanting to see what is the best possible lens I can get for landscapes. I will be using tripod, and a fast lens is pretty essential since lighting up here in the winter can be a bit dreary at times. The cost is not really a factor as I am only going to be renting. I am sure this has been covered to death, but I am not having much luck using the search feature on the forums. Any input would be appreciated. currently I have 18-55, 55-200, and the 35 1.8.

Thanks, Matt

--
http://www.flickr.com/photos/82210938@N07/