I used to do a lot of cycling. I rode Santa Teresa County park almost daily, and tried my hand in cyclocross racing, and even did the Sea Otter Classic MTB race some years ago. Done bunch of century rides, etc. over the past 15 years.
The most challenging ride I've done was we rode, completely self-supported on touring bikes, from Santa Cruz to Yosemite and back, camping along the way. We carried everything we needed, from food, cooking supplies to shelter. That ride was over 500miles total, because obviously we're not taking the freeway to get there, and limited highway cycling.
We were riding 60-80 miles a day and no less than 6000ft of climbing, daily.
We got real cocky when we saw that going through the Stockton area and the valley that 90 miles with 1,200 miles of elevation gain. We thought it was going to be smooth sailing - that was until the WIND hit us. The wind was way worse than any hill climb I've ever done.
I learned a lot about myself. The temperatures were gnarly and there were some roads that were so out in the apocalypse we had no way of knowing it was ever going to end. Serious, serious mind f*ck.
Anyway, don't cycle as much as I used to, but it's coo.