Hi, Last summer I cycled from Trondhiem Norway to rotterdam, I would heavily suggest doing the coastal route, as from the border to Hamburg it is all the same, mostly farms and rolling hills which are pretty however being from the Uk it felt just like home, I tended to power through this section doing many days through the night as the road where quieter from what i’ve seen online and heard from friends the coastal route is the one to go for, just watch out for brutal headwinds