Hey, writing wireless now from Shasta!
My eating plan is to mimic what I've been doing in my long training rides, which have been up to 80 miles.
These days I am carrying a bottle of plain water, and a bottle of water with Nuun electrolyte tablets. I also carry a third bottle that I can either drink or dump on my head to douse my hair if the weather is really hot.
I have been eating a combination of Payday Pro candy bars (just like regular Payday bars, but with extra vitamins, like the B's), Power Bars, and CarbBoom gels with caffeine.
On some of these rides I have had a midway yogurt with almonds, and that sits well for me, but that is only when I'm close to home and can stop there for lunch. I might take a few almonds on the bike with me in case I get hungry and want some extra protein with fat.
I plan to stay away from any real foods at the rest stops, because I find them unpredictable for me. Sometimes something will sit well and work (a bagel, some fruit), and other times the very same thing will make me sick.
For me, the one trick with eating just the bars & gels, and the same ones all day at that, is that toward the middle/end I can find I haven't eaten quite enough. So, I really have to watch the clock to make sure I'm eating enough.
Finally, for me, I like to alternate maybe 1/4 or 1/2 a bar with a few "sips" of gel. That works better for me than eating a whole bar at once, or a whole gel at once.
Side note: I live at sea level, and I'm here in my hotel room at between 3000 and 3500 feet. The ride goes up to about 7500, and at home, the highest I can get is 5000, and only for a short time at that...just the top of the hill climb. I can really feel it. The elevation is the one thing I'm a little concerned with. Hope it doesn't sap too much from me!
"The best rides are the ones where you bite off much more than you can chew, and live through it." ~ Doug Bradbury