Scandinavian tour

We are planning a 6 week (approx) tour through Scandinavia to see the midnight sun at Nordkapp in northern Norway.

The intended route is from Calais through Belgium, Holland, Germany, Denmark, Sweden to Nordkapp. The route back would see us following the Norwegian coast south before crossing back into Sweden and down to the Oresund bridge.

Has anyone done a similar trip and can recommend good campsites etc. Information on must see's and do's on route and things to watch out for would also be very welcome.