What about fences? I see that people have the right to roam but how are fenced-off areas dealt with?
Not to fence off people, need good reason like dangerous industry, farming animals and such, even if there's a fence you can still enter the land. Can't even put up a sign saying it's private land without permission.
Let's hope people will use it and invade his land whenever he visits.
That's the whole point, it's not invading. In the nordics, land outside of your immediate yard is for everyone, and there aren't many exceptions to that. You get exclusive access to financial gain from it, that's it.