Consistent with what Mayanorange said, when I have a big ride, which are almost always on Saturday, Tuesday is the last day that I ride hard. I'll usually do an easy ride on either Wednesday or Thursday (or both), and rest on Friday. Stay hydrated, eat a generous meal the night before. I eat a lot of carbs anyway, so every day is carb loading with me!
Morning of the ride, I drink a big glass of water first thing. Yes, it means more potty breaks, but dehydration usually gets me before hunger does. I then eat a bowl of oatmea and some yogurt with honey. I eat a banana about a half hour before the ride.
I'm making better use of my top tube back for long rides. On my most recent long ride--RAIN--I put snack size bags of cut up pieces of PayDay candy bars and Clif Bloks in the bag and ate them between official stops. The stops at RAIN are every 35 to 40 miles, so having a snack every 15 miles or so really helped my energy level stay constant.
I would also suggest taking a moment at each stop to stretch--especially your hamstrings and low back. Don't stay too long at the stops though. Keep moving!
Good luck with the ride and have fun!
Live with intention. Walk to the edge. Listen hard. Practice wellness. Play with abandon. Laugh. Choose with no regret. Continue to learn. Appreciate your friends. Do what you love. Live as if this is all there is.
--Mary Anne Radmacher