I could but the track is only 2.25 miles long, so even moving the start/finish straight to D Street I'm afraid the course maker's limitations will still make it to big.
But I'll give it a go for you anyway fella.
From cypher st (turn 10) to fargo st (turn 9) is 610m so I can put the start/finish there as the original s/f is only 380m ?
Unless you want me to make the track slightly bigger ?
Here you go fella.
https://www.gran-turismo.com/us/gt6/user/#!/friend/Mr-6rumpy1/course/1562106/View attachment 468295