Paisley to Pamplona (Scotland to Spain)

This summer I'm cycling to Pamplona from Paisley with a Canadian friend. We're raising money for an Indian Prosthetics charity, and looking to complete the trip between the 16th of June and 4th of July.
Any advice for the route and things we must see would be hugely appreciated!
We're taking tent-hammocks so looking to sleep in them most nights, but a warm shower would be great every now and then!