Valentino Rossi The Game Compact

Unfortunately, there is no in game statistics menu, however every race event you do in the game is with a 2016 MotoGP Bike (excluding the historic events), so you don't need to worry about the bike.

When racing, ensure that you complete the event to register your mileage.

The 500kms is roughly 136 laps of the Sachsenring (500km / 3.670km = 136.2 laps).
After the 25 online races I had completed roughly 275kms; therefore needing to complete a further 225kms, which equates to 21 (3 lap) races of Sachsenring (or 63 laps).

You can of course choose any track to reach the 500kms and the trophy will pop as soon as you’ve hit the distance, even if it’s mid-race.