Well - I've only been to a couple of drag racing events - but I'll weigh in:
You'll probably find the 200-500 a bit long. I took most of my on track shots at 200 (longest lens I had at the time) and I think that 300 would have been the most I could have seriously used.
Take a wider angle fast lens for walking round the pits. There will be lots of opportunity to poke your camera into often darker) places where cars are being worked on.
Don't use too fast a shutter speed on the "action" shots - pan the camera to get motion blur of the background (and give some impression of the speed).
Don't be afraid to burn shots - use burst mode to nail that image - you can always delete the dross later.
Take ear defenders. Nothing worse than missing a top fuel burnout because the noise made you jump when pressing the release (it has happened to me - oops!)
Watch what the press photographers are doing - they probably know the best spots.
I usually try to mix up about 1/4 of the way down the course (gets burnouts, starts and high speed passes), behind the cars and pits for my shots. I've NEVER had a good shot at the finish and have stopped sitting there!
Oh yes - be prepared to get frustrated
Hope that helps.