Okay here's my prediction for RPG in Canyon: There will be none!
Even though the setting would make for some great adventure tracks and some of the blocks would be well suited for RPG, the handling of the car is really a killer. The car can not move on the spot...you first have to accelerate a bit and drift to turn. Slowing down the car takes very long, unlike in Stadium. It is very heavy, so crazy stunts in the air are not possible because the car immediately falls down. Also when landing after a jump there is a high probability that the car will flip over itself if the car wasn't aligned perfectly horizontal. So bumpy stunts are very difficult too.
Blocks: Some of the blocks would be well suited. But they are most often way too rich in detail, having all sorts of polygons that distract. Also small transition pieces or other small pieces like in stadium are mostly absent. Maybe later when block import is enabled this will make some RPG's possible...
I'm actually very disappointed with the editor. I thought there would be much more possibilities to make something creative. I'm probably not going to build any tracks as it stands now.
But modding is still quite fun. Got this result after 30min of fiddling:
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