Yep - put the stuff on the bike, not on your back. You need the evaporative cooling. White sun sleeves on arms and legs. White Halo cap inside helmet if you're bald like me. Use a HRM and watch your HR. When it goes higher than it should for your effort, you need to get in the shade and drink until it comes down. For how much to drink, my rule is enough so that I pee about every three hours. If I don't pee, I sit in the shade and drink water and take electrolytes until I can. I use Endurolytes and take one or more caps every hour. It's not safe to ride in the heat the same way you'd ride in cooler temperatures. It's going to take a little longer to cover long distances.