Any riders in The Netherlands?

Yes sir, living in The Hague myself. I'm not very knowledgeable about shops in your area, but you could ask around at www.motor-forum.nl
Welcome to the Netherlands and enjoy our mostly flat, straight and boring roads with sometimes insane variations in speed limits (some highways have 80/100/120/130km/h in a span of just a few km's). Luckily Germany / the Eiffel is close by you and a very good riding area.

Np. roundabouts are a very welcoming variation in between the straight roads for me
I have only done one trackday myself at Lelystad, which is the cheapest but also not very large. Of course Assen and Zandfoort are well known, but a lot of people go to Belgian tracks like Mettet and Zolder because they're cheaper.
I forgot to say, if you need any second hand parts www.marktplaats.nl or www.speurders.nl is the way to go. There are a lot of online shops for regular maintenance parts like www.tenkateshop.com or www.mlmparts.com (these are just off the top of my head). If you have any questions, don't hesitate to ask.