Bob,
Pidge will have some tents and chairs for us (we've bought them in previous years and left them with him).
He also brings a large marquee and cooking equipment.
Bring along a sleeping mat and bag (unless you want to buy cheap ones there), couple of changes of clothes, falling over trousers, the usual.
It has been known to rain (last time was Weds / Thurs of 2005 race week). It's hot and sunny during the day, but cools off at night (it is March, afterall).
You need to buy a 4 day superticket at the gate and a parking pass for the car.