@jShort - I get that if you've got goals that include "better than fourth" then you're going to focus on the changes you need to make to do better, but you really should take a moment and recognize that you actually did pretty good there. Jeff & Pearl are right - they've both a done a lot of longer stuff and they both know their shit. (I think Jeff is probably pretty close to having done every endurance race there is at this point, so there 's a source of knowledge there for sure.) I can't offer any thoughts in terms of numbers - I've never used data
during a race to tell me how I'm doing. I could give my reasons for that, but they wouldn't and shouldn't matter to you. The only thing I read that I think you might want to work on is the statement you made about cramping coming on suddenly. I don't know if that played out exactly the way you described it, but that really shouldn't happen. If you can't tell ahead of time when cramps are coming, then either something is off physically or you're ignoring the cues. Managing effort and how your body responds to what you're asking of it is really the only difference between an XC race and and endurance race. And knowing what to do when the first signs of cramping appear is one of the most basic things to learn because it happens to everyone who goes for endurance sooner or later. For me, that has always been about moving my body more - more time out of the saddle, slowing cadence, stuff like that - I look at it like this: if I detect those first twinges that cramping is on its way, my entire focus becomes about how long I can put them off. That's all. And that doesn't necessarily mean slowing down. It just means finding different positions to cycle through (e.g., more forward on the nose of your saddle, then out of the saddle, then sit back further, then stand again, then repeat.) The idea isn't to slow down, it's to distribute the effort around to different muscles to give all of them chance to relax at least a little for a bit. If you can do that and keep them at bay for even 20 minutes, then if you drink or eat enough in that time you might even just put them off entirely. In the end, it's just about keeping them at bay for as long as you can. And sometimes it won't work - like if you're body isn't quite up to the effort that day, there may be nothing you can do to stop it from rebelling against your effort. But you can almost always at least hold them off for a while if you're paying attention.
But, seriously - if cramping because you are going out too hard is the biggest issue you are having after only recently starting endurance stuff, then you're in pretty good shape. You absolutely will work that one out.