2013 camping costs and best routes in Northern Europe for cyclist?

Hello all and sorry to ask a question that must certainly have been answered somewhere here already; I looked and just can't find it!
So, next month I'm going to bike from Brittany across Belgium, Holland, and end the trip in Hamburg.

What are the average camping costs? Wild-camping options east of France?

If caught in too much rain, is there a warm-showers equivalent in Europe? I host here.

I've cycled extensively in Europe, especially in France, with about 50/50 wild and paid camping. Back in the late 90s/early 2000's it was cheap and wonderful in France and more expensive for the little bit I did in Holland, so current cost/info would be much appreciated.

Also any advice on car-minimal and most historically beautiful route appreciated. I know NE France can be rather unsightly so am prepared for that, but I know little about the route east of that.

Thanks

Edited by: solarisglobal

You could try posting here. Loads of Brits camp in Europe

http://forum.ctc.org.uk/viewforum.php?f=16

An answer to my own question, having done the trip: most campgrounds in N Europe are closing any around sept 15, give or take 2 weeks on either end. Count on 5-12 euros more or less for cyclist. Respectful wild camping still an option, knock on the landowners door ( and pull some weeds in the garden etc if there's a little task you can offer!)