All good advice so far, but I'll repeat.

Talk to people. Admire all the neat bikes. Sunscreen. Stop and enjoy the small towns along the way - those towns work hard for this, they need a reward. Stop at roadside watermelon stands. Sunscreen. Lip balm. Take pictures. If you can find the shower set-ups take advantage of them - it's money well spent. Don't forget your tire irons/pump. Sunscreen. Have fun.