Edit: Video is no longer available, will look for another one soon. (Posted March 2022.)
So, there's a huge shortcut... a 1 MILLION credit/xp snowflake in Curnoe's Moustache in the Rockies. It'll instantly get you from level 1 to level 9.
Every now and then it isn't there (very rare). If so, switch from race to trick or vice-versa, or restart the game, or go offline and check that way so the track will reload and it should appear.
All credit to youtube user mannymax for the vid.
Edit: I've just gotten this for the second time (with a different account) while online. While geotags might technically cancel snowflakes this one was there first try both times, so I wouldn't worry too much about being online unless you fail to find it.