Sounds like an awesome race. I'm way out in the PNW, so I won't be doing that ride, but I have some awesome (awful?) climbing rides planned for this year. Nothing as steep as the MWARHC, though.
The Bellingham 300k has a single climb; Mt Baker. 25 miles and 4100' of gain. Not steep, but the summit it the 100k mark, so when you reach that, there's still 125 miles left to ride.
The 3 Volcanoes 300k hits Mt. Rainier, St. Helens, and Mt. Adams. There's nearly 12,000' of gain and about 15 miles of unpaved dirt/gravel roads.

At 235 pounds, I'm not really built for climbing either, but I love doing it.