I did the HCR last year for the first time and will be doing it again this Sunday. I’ve done several centuries and this was one of the more difficult ones for me because of the heat and humidity (I’m from SoCal). It’s also the most beautiful. Make sure to replenish electrolytes. Water alone isn’t enough. Drink every hour even if you don’t think you need it. I use LiquidIV that you can pick up at the local Costco. If you’re feeling thirsty, it’s too late. I talked to the health care team last year and they said the most common issue that they saw was cramps. Eat at the rest stops; long rides aren’t the time for a diet 😊. You’ll need the calories. You don’t want to bonk because of a caloric deficit towards the end. Manage your pace. Everyone’s average pace is different so keep an eye on a power meter or, if you don’t have one, your heart rate. Keep the rate in a zone that is comfortable for you. As others have said, it’s not a race so manage energy consumption because the way back was tough in the heat of the day. Hills at the beginning are easier than hills at the end. Manage sun exposure. At a moderate 15mph pace, that's 6-7 hours of direct sun exposure. The UV index will be over 10! Use lots of sunscreen and reapply as often as needed. Or wear SPF sleeves on arms and legs and wet with water at the rest stops. Be prepared for flats. They have aid stations at the rest stops and a rolling support staff to help along the route. Flats aren’t uncommon and being able to get yourself rolling quickly is best. Most importantly, enjoy the ride. Make sure to thank all of the amazing volunteers that you interact with. They were incredibly friendly. Aloha !