I went to the V8 Supercars earlier this year. Downtown Austin is such a great place, 6th Street is great for food, drinks & music. The locals are very friendly too.
The food I ate in Austin was the best I had for the whole US trip this time round.
It was about 25-30 mins by coach from downtown to the track. Talking to coach drivers they told how long it took to get in to car parks in a car, big queues. I'm sure those who went last year can advise
So depending on your budget, I would suggest somewhere in downtown, it will be going off I suggest.
And if no one else has suggested, try Salt Lick
Not sure how you would get there without a hire car though, maybe Greg Weld if he is in town could take you, I believe he likes it there.