Even though I didn't use a water shader, this took 5+ hours to render. Some areas in the river were hard to compute, I guess.
Martin, I did use some of your canyon preset nodes, but not all. Was hard to just fit in, as I used other compute terrains nodes and a too complicated setup, and I lost the rock islands in the river because of your 'patch 5 compute node'. In the end I just used the redirect but ten times smaller, and the angled strata shaders, and my own colors. I think your preset is great, but for using it to build upon, not fit in.