Dude ... you certainly get around !
It's easy, if you know where to go.
Look for a map of the Netherlands, you'll see there's a small part south of it, and it's exactly there I crossed it. From Maastricht to Vetschau (near Simpelveld, still southern Limburg (province))
But I've done it before. From Leer (Ostfr.) Germany, to Charleroi, via Utrecht. That's really crossing through 2 countries!
But that's also due to the fact that European countries aren't that big, compared to Canada. (even though some countries claim half the world's territories, like France)