So I realised the other week that the free rocket wing taster events also count. This saves doing some of the more ridiculous races (looking at you boardsleigh).
Can now confirm, thanks TheProwlerKing, that the Rocket Wings DLC doesn't count, just the 3 freebie ones.
Obviously I can't give you exact guide for every event, but if like me you were missing about 5 gold's for years, this might be a lightbulb moment.