Google maps link to the karting track we call our home circuit.
https://maps.app.goo.gl/HdAGKoSMujQDJKbp7
Narrow, short, twisty. Great for training riding technique. 8 metres elevation change in a small space. Reasonable run off areas, low top speeds. So I can tell my son to just go for it.
My boy's favorite, Pesämäki circuit at Honkajoki, Finland.
https://maps.app.goo.gl/Ay6z9nsbgKfQeiLj8
Just perfect for a youngster with a 250. A lot faster than a karting track, half the size of a proper racing circuit. 400 metre main straight, 5th gear.