Thanks for all replies, clarifications and suggestions. Really helpful. I hiked the public part of the park (Het Loo) for a couple of hours. Did indeed come across a wild pig family, not sure who scared who the most.
For me, an activation is about the whole experience; hiking, setting up, enjoying nature. I must admit that, although I really like the radio part, this only an addition to the rest; the icing on the cake basically. If it fails, soit. So, if I cannot find a nice location where one can sit at ease I will not set up my equipment.
Foy anyone interested, in the 90 meter contour there are some really nice locations to stay a bit longer. Much nicer than sitting beside the main road or the stress (if you are sensitive to it) of being fined because of trespassing. ;-(
Anyway, I think that we hams should try to respect laws and regulations as much as we can, especially if they are meant to protect a sensitive part of nature. We already have so little of that.
I wish you all great activations and look forward to work you al. S2S of course.