Hey Elizabeth - welcome to the board! You'll find many good ideas here. For one, how about
cut-up fruit (watermelon, oranges, honeydew) in a bowl with a tight lid, chunks of cheese, crackers, shelled walnuts, or almonds, and a bottle of wine? Sunscreen, some citronella candles, and an iPod would finish it off nicely.
I remember going to 4th of July picnics before the fireworks, and we were always jealous of the families that thought ahead enough to bring blankets, lawn chairs, a vase of flowers, candles (although true, it was at night), and little gourmet munchies while our kids were running around with potato chips and sno-cones. ;o)