What's the most off-the-wall thing you've done for the sake of book research?
Hmm -- so far, it's when I went hiking across the Kilaueia crater in Hawaii, while jetlagged and badly out of shape because it was February. That's a hefty hike, across GLASS-COVERED JAGGED GROUND THAT IS STILL HOT FROM AN ERUPTION DECADES AGO. I could've gotten really hurt. :) Don't do that. :)
But fortunately I was fine, and I even stopped to toast some spam sushi over a heat vent for a delicious geothermally-warmed lunch.