Well, you use the warped SSS as a mask for the basic (first node) terrain colors, and feed that through a displacement shader to raise the sides of the soft valley (so a wide river area is left flat). Then you can select a range of the same warped terrain colors with color adjust shaders and displace more (for some sort of ravines). And use stretched (XZ) PF for the strata.
The river follows the same basic warp, but has an additional warper after it for the 'sinuses'.