I can't give you anything exactly specific to your route (I guess you're going inland), but I recently got back from my first "Euro Expedition" where I popped over to Le Havre from Portsmouth and then essentially followed the coast of western France, Northern Spain, coast of Portugal, back along the south coast of Spain to Gibraltar and on along the Spanish coast to southern France and back up the middle via the Millau Viaduct (astounding!) to Le Havre and home. I used a mixture of A roads, B roads and a little bit of motorway.
All I can say is that:
Petrol is only a little bit cheaper out there than it is in the UK, so for working out an approximate fuel cost, use UK prices and you won't go far wrong (and may have a bit left over from the petrol budget for a treat).
Tolls didn't seem too expensive in France, but the Spanish ones seemed a bit dearer. Tolls are almost always avoidable, but avoiding them may add a fair bit to your mileage. I just set my TomTom to "always avoid tolls" on the days when I was happy to just bimble along on the minor roads, although it has to be said that when I did use them, the toll roads were a pleasure to ride in terms of road surface and relative lack of traffic.
I don’t know about the Pyrenees as I skirted the edges of them at the coasts.
Camping was seldom a problem along the coast and always quite cheap, at eight to fifteen euros for me, a small tent and the bike. I guess if there's two of you could add on another five to ten euros per night for the extra person. Campsite facilities were always good and I never found a dirty / smelly loo or a cold / dirty shower block. Many of the larger villages / small towns have municipal campsites run by the council and these are pretty good and clean and not far from shops and restaurants.
I never had a set destination for the end of each day, just a rough approximation of where I wanted to end up and when it got to about 5.30 or 6.00 o’clock in the evening I’d start looking out for a campsite or a cheap hotel or B&B. I was generally on the road by about 8.30 or 9.00 o’clock each morning, so had a good days riding under my belt by then.
By the way - It's obvious but don't forget it's going to be HOT, especially in Spain, so make sure you have plenty of water with you to drink!
Enjoy!
