I was in Spain too mostly on the eastern side from the beach all the way up in the Pyrenees and back into France, did stop plenty of places and same.Europe isn't all synced when it comes to 'camping/living' in your vehicle. France is probably the best as they have infrastructure like you mentioned. And it really does depend on where you are in said country.
Spain is HUGE and most of it is not used in anyway. So it's WAY easier to find places, especially inland. And off-season (now) is the best time to do it.