All the above suggestions are good.

Are you cooking? Building a fire? If so, will you collect or buy wood? You might want a saw or hatchet. I use firestarters (either homemade or purchased).

You'll need something sturdy for food storage -- can your food supplies go into a car overnight to be safe from insects and wildlife? If you are storing food in a cooler with melting ice, be sure it's securely packaged so it doesn't get waterlogged.

I never bother with chairs; I cut a piece from an old closed-cell foam sleeping mat and sit on that.

Remember that if it rains EVERYTHING gets wet. I take extra garbage bags, several big Ziploc type bags and no cotton clothing.

I second the suggestion of a hands-free light source (headlight). Good investment if you ever live through a power outage, too.