Shepherds Caravan

This one was fun to do, my better half requested I make this, but I was unable to find a suitable plan, so I had to freestyle with the help from a photo from the web. Pleased with how the roof turned out, I was wondering how to get the curve and what material I should use, in the end I settled for MDF and the ridges, allowed just enough bend. Not over sanded, as I wanted it to feel used and rustic. ( My excuse anyway).