Well, I've lived in the old town section of Justin for the past 2 years, and while it did take some time to adjust to not having a Starbucks and a Target right around the corner, I have really learned to love it. Everyone here is very laid back and friendly, and I love the fact that I can feel totally safe walking my 3 year old and our dog 5 blocks every Sunday to get a paper, without worrying about someone tearing down the street at 45 miles an hour. As a matter of fact, most everyone slows down to a crawl as soon as they see anyone in the street, and my kiddo loves that people will wave to you from their car while they are driving and we're in our front yard. He gets a big kick out of being "neighborly".
There are some tricks to living here during a race weekend, but it is doable. As the previous poster said, you just have to time it right. When race weekends come, and we want to go out to eat, we usually head north to Denton and have never had a problem coming or going. The only thing you'll see differently in town on race weekends is a line at the donut shops and a packed Sonic. Other than that, the race fans tend to stay out of Justin.
As far as eating out, there is a fantastic Mexican food restaurant that makes killer fajitas in town called Chios, and there is a large cafe called the Lonesome Spur that serves a great breakfast, lunch, and dinner. Roanoke and Denton are only 15 minutes away, and both are full of great restaurants.
I hope this helped!