That's surprising. I was under the impression that landing outside of an airfield is only permitted in a few states and parts of Canada? In Europe it's generally forbidden (with the sailplane exception of course).
Look on YouTube for folks flying something like a Kit Fox (start with Trent Palmer). You'll find some fun videos of some cool spots they land. Also, STOL drags are cool to watch.
In the US, you may generally land anywhere the landowner permits it. There’s lots of publicly owned land, and although it’s up to individual management agencies, you can generally operate a plane wherever you can operate any other motor vehicle.
Crop dusting is still a thing. I live in the middle of nowhere and there are several strips of flat grassland that are landing strips for crop dusters.
