Thirty years ago I spent three months as a USGS intern as part of a team taking depth readings on explored portions of caves.
What makes Mammoth so cool is the huge size of the passages. But, I don't think I'd have been nearly as impressed if I'd not spend three months mostly crawling through the tiny passageways that comprise the vast majority of most caves.
Wyandott cave once ran a 12 hour 2 person + 2 guide tour into the tighter areas. If they're still running that tour then I highly recommend it. At the time, it was damned near impossible to ever see a cave in that way unless you had a friend already hooked into the spelunking community.