I have a friend who likes to walk, bike, camp and exercise the freedom to be wherever she is as long as it's not disruptive of others. For her it's a spiritual need and a philosophical/political attitude. But she's well-educated, a confident conversationalist, and tends to be cooperative and genuinely understanding if she's caught doing something that breaks the local expectations.
I've personally heard many stories about North Americans visiting 'this or that' part of Europe (although not Netherlands in particular) and being shocked by how much more welcoming/sympathetic rural or suburban people are of travelers walking across or even camping on "their land" compared to North America where a strict "no trespassing" is the norm and 'unknown' people anywhere will likely get rudely unwelcomed by the police.
Is it socially acceptable or tolerated for someone to camp on someone's property in Netherlands?
Also, is she likely to find like-minded people "on the road" there?