book a hotel now, seriously.
If you can only make it one day and want to see cars that day is Saturday. Sunday is a waste in my opinion.
DRINK WATER, Ask me how I know. I was that loser that thought he would man through the heat and ended up spending half the day with the fairground medics people (by the way great people) Heat stroke sucks especially when you have to drive 8 hours home with it.
Sun Screen
Talk to the car guys - see a cool car? thank him for bringing it out.
See a car you don't like/ not your style? keep it to yourself. I saw some guy saying out loud "look at this piece of sh!t" you know what? the owner likes and takes pride in it, move along idiot.
Go see Mr. Norm, he is definitely a hero of mine and he is always there.
You go once your addicted for life - so be prepared to tell your wife you are now reserving this weekend trip for the rest of your life!