Denmark has a very nice site for AIS, nav warnings etc.
Try these:
http://www.slv.dk/Publikationer/AIS_...ortegnelse.htm
http://www.ftk.dk/milais/images/Navwar/2003-07-10.jpg
Avgas is about 6Kr (1 Euro) / litre
Lelystadt is a nice field, but watch out for meat-bombing
Sylt area can be quite busy.
Fresian Islands have quite a few nice fields. For a taste of the old British Empire you may like to visit Helgoland, about 400m and PPR essential.