Steve, the caldera gets a good bit of snowfall every year - this one being an exception. I've never heard of any flooding issues up there. There are plenty of streams and other outlets for the water to drain off. The caldera is about 14 miles in diameter and sits at about 11,000 feet. Walt Longmire being no mere mortal sheriff, he could hear a prairie dog popping up from two miles away.
Drew, years ago we did a topo of the Grand Canyon in urethane foam (cutting about 5 x faster than wood with excellent detail) that was almost 4 x 8. Still took a long time but was very impressive. One of the issues you run into with exaggerating the elevations is the tool length. We did the finish pass on the one in the photo with a 1/8" bit and came so close to bottoming it out in a few places.