What do you think about holidays on russian side of Kurshskaya kosa?
(http://maps.google.com/?ie=UTF8&ll=55.1 ... 2.8125&z=9)
I know that Lithuanian side has a lot of hotels and very nice places for relax...

It looks even more appealing without people and hotels.

I have travelled from Klaipeda to Karliningrad using the Kurshskaya Kosa, on the west side, i.e. the Baltic sea side there are no buildings there. Yes there are hotels there on the east side, but not very big, and they fit into the landscape very nicely. They cannot build on the west side (the side that adjoins the Baltic sea), also it is national park. On the Russian side I did not see any building at all, though we did not stop. It is very beautiful.
It is a very nice place to relax, and more important it is undeveloped.