To get this trophy you must Star every main path level of a planet in Story mode. This means getting 100% of the prize bubbles and placing 1st in each. As the game remembers which prize bubbles you've previously found, this can be done in several tries.
The final planet of the game (Hoard, Sweet Hoard) only has one level (The Garage at the End of the Craftverse) and relatively few prize bubbles. It also isn't a race, so no need to worry about finishing in 1st place. Hence, it is the easiest place to unlock this trophy.
Without spoiling too much, you'll have to do a lot of driving around in the same place and almost can't miss getting all of the prize bubbles here.