Regarding Norway, it being private land wouldn't matter much. It is written in Norwegian law [0] granting the right to travel the land without too many restriction. Private property is not one such restriction. One should avoid farming fields during spring, but in broad strokes that's pretty much it.

This includes the right to forage (berries, mushroom, whatnot). Though hunting and fishing can be quite restricted. Motorized vehicles have their own set of restrictions, but trekking, biking, sailing, etc are fine.

So, one cannot for instance fence off the access to nature, like a "private" beach etc. And camping is allowed everywhere not within 150m of a house/cabin with residents up to two days, though relocating to somewhere else would be fine. Farmland is again an exception, and you should ask the owner for permission.

PS: There are local exceptions everywhere, so be sure to check that. Some waters are protected, etc. Some regions are considered "protected nature", which doesn't trump "allemannsretten" (the aforementioned rights), but there can be other restrictions. And in all cases, it is expected to not leave behind garbage or cause damage.

[0]: https://lovdata.no/dokument/NL/lov/1957-06-28-16 (In Norwegian)