Monochrome, particularly off sepia, really doesn't suit this image. You should be careful about using monochrome when it doesn't add something to the image.
I usually only use b&w or sepia on a landscape if there is a lot of repetition or intense texture to hold intrest. This is a nice shot, but some vivid colors would have been beautiful!
Very nice use of duotone, but it to me its seems somewhat middle-of-the-road 'muddled', think I would have tried some sharpening or boosted the graininess. Really like the framing.