Yes, the Phoenix race will be worth going to, imo. (Or any NASCAR race, for that matter.)
Yeah, maybe there isn't any on track camping allowed, but there is a park located on the west side of PIR that has been known to allow overnight campers to set up, or so I've been told. I only live 15 mins from the track and get to sleep in my own bed, so I can't confirm that.
I will tell you, however, that the Houston Texans will be in town to take on my Az Cardinals. The Cards stadium and PIR are located on the same side of town and a ton of folks will be heading west on the I-10 to attend either.
Get there early if you choose to not camp out. A lot of uninformed people are going to miss the first 30 laps of the NASCAR race or the 1st qtr of the local NFL game.
You can take that one to the bank.
Can't wait, man.