Gran Paradiso Island
Gran Paradiso Island is an official SuperTuxKart track.
This track has a nice gameplay, due to numerous turns, the zipper, the canon, and the "secret" path (the bridge). However the track is pretty easy to drive, except maybe the turns of the last part which are a bit tight for beginners. The track has an intented shortcut (that is actually an alternative path): After the sandy part, you can turn to the right to take the bridge, it saves around 4 seconds (zipper effect included). There's also a shortcut in this shortcut. It allows to skip almost the whole bridge. The recommended strategy to do it is using a zipper and then two yellow skids aimed at the end of the bridge. It is featured in this Tool-Assisted-Speedrun by Fouks: here