this trip for me was so long ago, I dont recall the details, but what stays with me (a really enjoyable trip btw) is that it was harder with the climbs than the Pyrenees, just a general impression but I trust my gut on this one.
Seems to me that the little ups and downs wherever a river came to the coast were the worst, and tiring. You'd be up from sea level a given amount, then at a river you'd zoom down a steep hill then schlep up a steep climb. Repeat.
Alpine and Pyreneean climbs are long but generally steady. I've had tougher days in parts of the western UK, where there's no climb longer than a few hundred feet in elevation, but lots of the terrain is corrugated - ferociously steep little rises, followed by very short descents that don't allow time for recovery. Interval training for tourists.