Not sure how well this will ever work out, but I was thinking of other sets that would be fun to combine, and here was something quick I came up with:
I need to work on the execution a bit, but the idea is this - combine the lava from the Lair of the Dragon God set with the river tiles from the Hinterland Forests and Hinterland Cliffs sets. I had to do some adjustments to the river tiles to make them less bendy (and I probably will do even more...) since most lava flow pictures I could find did NOT look like the lava went all zig-zaggy... I added a layer to darken the stuff around the lava flow so it looks more charred. I need to soften the boundaries between the charred and uncharred areas, but that's not hard.
I think it'd be neat to kitbash the SwiftScenic DeadFall: Deadman's Canyon set so that it uses Hinterland Cliffs textures for the rock face, and grass/dirt textures for the flat parts. Then I could make a volcano texture to let lava flow down.
Here's another version, this time making heavy use of some dead ground texture I made from another Hinterland Forest tile. I cloned out all of the grass, reduced the saturation quite a bit, then used that around the lava. I really hate the harsh edge between the lava and the ground texture, but I'm not sure feathering the edge will make me happier... I'll continue to experiment.