Thanks, TU. Have you found this method supercedes the Soft Lighting feature? The land really is heading toward having some complexity. I'll show the node network later, but it's built on moodflow's fire in the ground image of about a month ago. I followed his node network as seen in the pictures and, with some more questions answered by him, eventually came up with my own version.
I'll try some test renders to decide what might work best, but suggestions like this are always helpful to think about. Thanks!