OK, my oldest said I was mad, and she's right. But last week I ended up cycling for 2 days from SF up to Yosemite. It was one of those things that seemed doable knowing what it's like to ride longer distances, but still seemed daunting given the lack of ride support (disclaimer: I've done two double centuries but this was way different).
The hardest part of the trip was the climbing (no kidding), and the heat (turns out to have been over 100 on each day). As my friend texted me during the ordeal: loads of water, electrolytes, food.
The heat and hills combined to double team my sweat glands--you could almost just watch sweat pouring down my arms later in the day.