Freezing is not good. I've ridden in 33° sleet on a 200, which was not fun, but I was way under-dressed. If you're going off ride reports, 7500' is what it is, but if it's off a RidewithGPS map, multiply by ~.8. Ours is only 6600', meaning more like 5500'. Of course, I'm an optimist. I did a 200 a few years ago with 7000' which wasn't too bad because most of the climbs were relatively shallow. 8 hours ET. It's those steep suckers that rob my cadence that kill me.

I figure you can do in a day what you can do in a week. So if you're conservative and figure 9.5 saddle hours for the 200, and you're doing 9.5 hours for say 3 weeks before and then an easy week the week of, you should be able to do it fine. If you haven't been, you might try to catch a later one. Or you might be fine. It seems you've been very consistent. We've had a few 13 hour weeks, so I'm not too concerned about March 15, though my wife is.