Also what type of cladding would anyone suggest?

A version of one of these might work for your dilemma. Surely one of them can be tweaked to work for your window.

Looking for some advice on what to do with our A-frame house bedroom windows. Currently, there is a curtain track that goes across the window, but it leaves the top of the triangle uncovered - which isn't ideal when the sun comes up at 5am in summer! Any suggestions on what kind of window treatments might work? We don't want to permanently cover the top triangle, so looking for a solution that would allow us to cover (and uncover) the entire window.

Hi Michelle - It looks like treated pine to me, and looks as though it has been recently built. If you did nothing it would fade to a grey colour within 6 months or so. This would probably blend in with the house quite well, and you wouldn't have to do a thing! Otherwise I would stain it - there are lots of stains on the market - see if there is one you like. A dark one would create a nice contrast with the house and make the fence look more like a feature. Good luck!