Can I ask what division were you in? (Public forum so if you want to keep private no worries).
And what was it that made so many cramp up? I started conservative but the exact same thing happened to me.I felt great the first lap and then had a twinge the first time up lookout and then was fighting them off the rest of the way. When I finished both legs seized and had no choice but to lay down and suffer. I went through a bottle an hour and fueled well. Only thing I can think of is the salt?
The hills are steep and short and never stop. But I live here so it’s not like I don’t ride this stuff all the time. I saw so many pull off from cramping. It was really weird.
But 4th despite all that is amazing. Lots of fast people out there this year. Well done!
Aside from hydration, I think folks are not prepared for the course. You need low gears for Barloy Spur and Lookout, and you need to stay out of the red zone pretty much everywhere else on the course (including the start). Cramps are your body’s way of telling you not to ride up Lookout again. 
If you feel that cramps are on the way, you have to back off the pace. That doesn’t work on the steepest ramps of Lookout though.
For gearing 2x gives great range and gear spacing, but 1x with a big cassette and an appropriate chain-ring will get you there with a minor trade-off on top-end speed. For me, I need a 0.8 low ratio. Elite field is more like 1.0, i.e. same size chain-ring and smallest cassette cog.
I was in the 50+ division. Thinking about it - I think the cramps were a result of the multiple efforts during the course during the first two hours. These were a bit different than what I’ve done all year long. Like I said, it wasn’t overly hot to me and I was drinking appropriately. @Jolyzara you mention salt, but if I’m taking my advice the culprit is that I did not execute enough long rides with similar efforts throughout to mimic the demands of the course during my training in the weeks leading up to this event.
The course in and of itself was tame in that there weren’t really any technical sections or puncture risk sections which is welcome. @ukbloke you may be correct in that our bodies speak to us when we push too hard, but this is the A race for me and there’s no holding back. If I were doing the 90 miler, I can see holding back a lot, but I’ve already done two other races at similar distances without these issues, but also without the 70-degree temps.
I have some thoughts about my training leading up to the event that I may start a fresh thread about or add to another, but I may try a different approach going forward. Something along the lines of doing my second hard work out in combination with my long endurance ride on the weekend. Durability comes to mind My legs had more to push watts wise, but not at the 3-1/2 mark. Who knows what next year brings but given the opportunity I’ll take another crack at it.
I totally hear you @ukbloke. And as @Stevie_Dee mentioned I also could have used a few more longer endurance rides with some punchy efforts mixed in for race prep. Though hard to do in the short, cold days of winter (and once I hit 90 minutes on the trainer I start hating life).
I think I should have gone with a mullet set-up. I have 42 front and XPLR with a 46t cassette rear (.9ish ratio). I was fine getting up the hills but definitely had to push the watts. One extra gear might have been a touch slower up the hills but less strain (while fatigued) to help ward off the cramps. Here’s my gear breakdown.
Lessons learned. It was a fun race minus the cramping.
The gear breakdown is interesting. I bet there’s 20 minutes where you would have benefited from a lower gear. And you could trade-off the couple of minutes in the highest gears without losing much. You don’t need wider range, just a 38T chain ring.
I went from an 11/34 cassette to 11/39, and this made a huge difference on Lookout. I did the 3 lap race, and the 3rd time up Lookout is just brutal. I switched to road shoes this year so placed a big bet that I wasn’t going to have to unclip or even walk, and thankfully I didn’t.
