St. Dionys lost a lot of its appeal when they had to build five new holes after losing some of their original ground. (close to Dionys is Schloss Lüdersburg. They have a parkland course (Old Course) which is rather bland and a perfectly fine Nicklaus design, the Lakes Course).
When you drive in from Amsterdam, you'll probably drive through Bremen. You could try to play Club zur Vahr Garlstedter Heide, I really like the course. It is, like Falkenstein, member only on the weekend, but maybe you're lucky if you ask friendly. They have not much play on weekends which makes it really fun.
You could also play the Hamburger Golf Club Hittfeld. It could use some width, but otherwise is a fine tree-lined layout.