Hi Jane, I completely disagree with whoever told you that there is no pretty scenery, Allowing for the fact that beauty is always "in the eye of the beholder", in my opinion the Norte offers some of the most striking scenery that I have seen in 9 years of walking Caminos (Frances, Portugues, Primitivo and 1st half of the Norte).
There is undoubtedly a percentage of road walking, but you get that with every Camino. There are very definitely lots of hills in some sections and fewer and smaller in others. My experience last year was coloured by being made redundant just before leaving for Spain and the negative impact on my fitness, morale, etc., but I really enjoyed it, despite slipping and badly bruising my coccyx.
I think that you are going to start from Bilbao you will have the hardest hills behind you. Have a detailed search through the various threads on here and you will find oodles of information to let you plan out a trip that maximises off-road walking.
My wife and I have our plans set and fly from Dublin to Santander on August 28th ready to walk from Ribadesella to Santiago.