Well, I never really understood all this obsession with food during rides and guys who are non-stop shewing on club rides, this just doesn't make sense to me at all. Really, you don't need anything special for such a ride. Basically, just eat well before the ride (like a couple of hours before, also on a previous day) and after the ride. During the ride, especially a slow one and with the stops every 35 miles, eat whatever you like but in moderation, don't eat much - it'll be difficult to ride on a full stomach and you don't want to make your stops too long because then your muscles will cool down and it'll be harder to continue riding. Just eat something during these stops and rest a bit, you don't need anything every hour. I, personally, usually just grab some coffee + sandwich or bagel with cream cheese or ice cream (particularly good on hot days).
Now, it looks like I'm more than 20 years younger than each of you, I've done centuries several times and I don't really feel tired after finishing. However, next day I can't put the same effort as on the first day - by far. Yeah, I can still easily do, say, 30 miles. But 80? I know for sure that I'll not enjoy doing 80 miles on the second day, I'm not in such a good shape yet. So, if your longest ride so far was 80 miles, you'll probably find it very, very challenging to do 108 + 82 in a row. Good luck!