I live in Austin and went to the inaugural event. The regular seating is rather small, and I feel that most of it is bench seating. I thought it was a bit of a waste to buy the seat when we were walking around most of the race checking out all the corners and sights, the track is beautiful I can't imagine not wanting to explore every part. The GA pass is a good bit cheaper as well. There are also paddock passes and a number of seating options that look rather cool.
When I went the entry gates were limited to one location on the track, so if you had seats in turns 10 or 11(which I did) then you had a mile walk to your seats from the main gate. That's been addressed since, along with parking to some degree. I don't think I would recommend parking at the track, since the track is in a rural location with smaller country roads to service 120,000+ people. There are shuttles from downtown and park and ride options 3 miles from the track that are faster and considerably cheaper than the track parking. And if you like to drink, the shuttle is a good option.