First off, yes, I understand this wasn't one run from top to bottom. It obviously took many attempts to get certain shots. And for the most part, he's IS skiing on grass/road/whatever.
That said, a couple things look suspicious to me...
:38 - :43 -- it looks wayyyyy to smooth. That's gotta be fake, right?
1:19 - 1:27 -- come on now... the start of the trick looks fake
1:33 - 1:36 -- this one's tricky because when he's entering the car it looks real... but how come there's no gopro angle for that shot? wouldn't that be the best shot in the video?
Perhaps I'll get ripped apart for this... however, I am a Candide fan and enjoyed the commercial.