I got this little dickie/vest thingie a few years ago, didn’t spend much. The company was 6-One, or Six-One, Six-1, something like that. Anyway, it’s sewn in a checkerboard pattern, each square about 3/4”. In each square is a little bead. Soak that bead overnight and it swellls up to fill the whole square. Imagine a gazillion of them full of absorbed water, all around your neck and upper torso, .... inside your Roadcrafter, .... zipped up tight to the neck and across the back. Open the cuffs, put it in gear, and when you hit 40mph you’ll feel like you’re sitting in a bubble of a/c. It’ll last all day, and maybe into the next. You’re wearing it under your t-shirt and the shirt continues to feel dry. Re-soak it for a few hours and it’s ready for another go. You clever guys can googlize this thing and find an eBay, Buy It Now item in no time, I’m sure. No ice, no cooler, no electric fan.