After coming (back) to GP4 2+ yrs ago I've downloaded just about every circuit I could find - and once in a while I load up a track that's new to me and I wish I had known about it at the outset. This is certainly one of them.
It dates back more than six years but if you've not come across it before you really should give it a look. It's so completely professional in every respect: great DAT, excellent colours, lovely elevations and panoramic views of the water etc etc. Highly recommended.
As always, credits go to the authors:
Gildoorf Rozencrantz
Paulo Blanco (Prblanco)
Ruben Greidanus (Turbo Lover)
(What a team...)
It's available
here