First go to community, race online, create race. Then go to game setup and change the track to Test Track layout A. Also, set the amount of laps as 50, make the opponents to 16, put the car class as any, make the opponents on proffesional.

After all that select the last car in Peguot, go to difficulty and make everything on difficult/hard, make the car automatic, then start race.

Now all you have to do is go to the left at the start of the race and don't go in any of the warehouses - so don't follow the other cars and just cut the corners short.

You should get from 90,000 to 100,000 XP. Repeat this as many times as desired.