3L+ for a full day game...as many snackies as I can get to.
The key (for me at least) is "little and often". At least a sip/mouthful of water every 15-30min...or every chance you get. At least something to eat (and Jerky doesn't count) every 30-hour.
Sipping fluids and snacking when you don't feel the need is far better than chugging a gatoraid and wolfing down a meal when you're thirsty and hungry.
Your body needs time to process stuff into nutrients and get it to the organs that need it (your brain will complain first). You can't force it to go faster (you can train though which helps your body adjust to strenuous exercise and processing nutrients).