On the last Grid Drive, we discovered a nice new track to drive on. North Island - Isle of Demonte. You cant fly on the sim (forced landing spot) so if you want to start from the top to go down instead, you must use the TP board from the bottom. The track rises 1000 meters.
Slurl: http://maps.secondlife.com/secondlife/North%20Island/6/101/266
The list of region and racing tracks can be found here: https://www.driversofsecondlife.info/p/region-and-racing-tracks.html