There are flat parts of WI? :O It's not all like Fountain City?

I double up on tubes and CO2 cartridges for centuries, and like others bring a few emergency gels and maybe a Clif Bar or something just in case. If it's going to rain the whole time and I have my rain jacket that has a big rear pocket I'll toss in a spare tire sometimes. I copy another rider I know now and put a few wraps of duct tape around a CO2 cartridge, it can be a little easier to boot a tire in an emergency with something sticky on one side. Otherwise a dollar does work. I've used cardboard when I forgot anything else, but that led to abandoning a dozen miles later because it started raining and the cardboard got wet and broke down.

If there's a rest stop with ice cream, which seems like a WI thing (Door County century has ice cream, the Bay City stop on the Tour de Pepin did too...) know which one it is ahead of time so you don't skip that stop. Ice cream is rocket fuel.